Skip to main content
Erschienen in: Diabetologia 8/2005

01.08.2005 | Article

Importance of mitochondrial superoxide dismutase expression in insulin-producing cells for the toxicity of reactive oxygen species and proinflammatory cytokines

verfasst von: S. Lortz, E. Gurgul-Convey, S. Lenzen, M. Tiedge

Erschienen in: Diabetologia | Ausgabe 8/2005

Einloggen, um Zugang zu erhalten

Abstract

Aims/hypothesis

Free radicals generated in mitochondria play a crucial role in the toxic effects of cytokines upon insulin-producing cells. This study therefore investigated the role of manganese superoxide dismutase (MnSOD) in cytokine-mediated toxicity in insulin-producing cells.

Methods

MnSOD was either stably overexpressed (MnSODsense) or stably suppressed (MnSODantisense) in insulin-producing RINm5F cells. Cell viability was quantified after incubation with different chemical reactive oxygen species (ROS) generators and with cytokines (IL-1β alone or a mixture of IL-1β, TNF-α and IFN-γ). Additionally, cell proliferation and endogenous MnSOD protein expression were determined after exposure to cytokines.

Results

After incubation with hydrogen peroxide (H2O2) or hypoxanthine/xanthine oxidase no significant differences were observed in viability between control and MnSODsense or MnSODantisense clones. MnSOD overexpression reduced the viability of MnSODsense cells after exposure to the intracellular ROS generator menadione compared with control and MnSODantisense cells. MnSODsense cells also showed the highest susceptibility to cytokine toxicity with more than 75% loss of viability and a significant reduction of the proliferation rate after 72 h of incubation with a cytokine mixture. In comparison with control cells (67% viability loss), the reduction of viability in MnSODantisense cells was lower (50%), indicating a sensitising role of MnSOD in the progression of cytokine toxicity. The cell proliferation rate decreased in parallel to the reduction of cell viability. The MnSOD expression level after exposure to cytokines was also significantly lower in MnSODantisense cells than in control or MnSODsense cells.

Conclusions/interpretation

The increase of the mitochondrial imbalance between the superoxide- and the H2O2-inactivating enzyme activities corresponds with a greater susceptibility to cytokines. Thus optimal antioxidative strategies to protect insulin-producing cells against cytokine toxicity may comprise a combined overexpression of H2O2-inactivating enzymes or suppression of MnSOD activity.
Literatur
1.
Zurück zum Zitat Fridovich I (1995) Superoxide radical and superoxide dismutases. Annu Rev Biochem 64:97–112CrossRefPubMed Fridovich I (1995) Superoxide radical and superoxide dismutases. Annu Rev Biochem 64:97–112CrossRefPubMed
2.
Zurück zum Zitat Gardner R, Salvador A, Moradas-Ferreira P (2002) Why does SOD overexpression sometimes enhance, sometimes decrease, hydrogen peroxide production? A minimalist explanation. Free Radic Biol Med 32:1351–1357CrossRefPubMed Gardner R, Salvador A, Moradas-Ferreira P (2002) Why does SOD overexpression sometimes enhance, sometimes decrease, hydrogen peroxide production? A minimalist explanation. Free Radic Biol Med 32:1351–1357CrossRefPubMed
3.
Zurück zum Zitat Scott MD, Meshnick SR, Eaton JW (1989) Superoxide dismutase amplifies organismal sensitivity to ionizing radiation. J Biol Chem 264:2498–2501 Scott MD, Meshnick SR, Eaton JW (1989) Superoxide dismutase amplifies organismal sensitivity to ionizing radiation. J Biol Chem 264:2498–2501
4.
Zurück zum Zitat Amstad P, Peskin A, Shah G et al (1991) The balance between Cu, Zn-superoxide dismutase and catalase affects the sensitivity of mouse epidermal cells to oxidative stress. Biochemistry 30:9305–9313CrossRefPubMed Amstad P, Peskin A, Shah G et al (1991) The balance between Cu, Zn-superoxide dismutase and catalase affects the sensitivity of mouse epidermal cells to oxidative stress. Biochemistry 30:9305–9313CrossRefPubMed
5.
Zurück zum Zitat Kedziora J, Bartosz G (1988) Down’s syndrome: a pathology involving the lack of balance of reactive oxygen species. Free Radic Biol Med 4:317–330CrossRefPubMed Kedziora J, Bartosz G (1988) Down’s syndrome: a pathology involving the lack of balance of reactive oxygen species. Free Radic Biol Med 4:317–330CrossRefPubMed
6.
Zurück zum Zitat de Haan JB, Cristiano F, Iannello R, Bladier C, Kelner MJ, Kola I (1996) Elevation in the ratio of Cu/Zn-superoxide dismutase to glutathione peroxidase activity induces features of cellular senescence and this effect is mediated by hydrogen peroxide. Hum Mol Genet 5:283–292CrossRefPubMed de Haan JB, Cristiano F, Iannello R, Bladier C, Kelner MJ, Kola I (1996) Elevation in the ratio of Cu/Zn-superoxide dismutase to glutathione peroxidase activity induces features of cellular senescence and this effect is mediated by hydrogen peroxide. Hum Mol Genet 5:283–292CrossRefPubMed
7.
Zurück zum Zitat Rodriguez AM, Carrico PM, Mazurkiewicz JE, Melendez JA (2000) Mitochondrial or cytosolic catalase reverses the MnSOD-dependent inhibition of proliferation by enhancing respiratory chain activity, net ATP production, and decreasing the steady state levels of H2O2. Free Radic Biol Med 29:801–813CrossRefPubMed Rodriguez AM, Carrico PM, Mazurkiewicz JE, Melendez JA (2000) Mitochondrial or cytosolic catalase reverses the MnSOD-dependent inhibition of proliferation by enhancing respiratory chain activity, net ATP production, and decreasing the steady state levels of H2O2. Free Radic Biol Med 29:801–813CrossRefPubMed
8.
Zurück zum Zitat Lenzen S, Drinkgern J, Tiedge M (1996) Low antioxidant enzyme gene expression in pancreatic islets compared with various other mouse tissues. Free Radic Biol Med 20:463–466CrossRefPubMed Lenzen S, Drinkgern J, Tiedge M (1996) Low antioxidant enzyme gene expression in pancreatic islets compared with various other mouse tissues. Free Radic Biol Med 20:463–466CrossRefPubMed
9.
Zurück zum Zitat Tiedge M, Lortz S, Drinkgern J, Lenzen S (1997) Relation between antioxidant enzyme gene expression and antioxidative defense status of insulin-producing cells. Diabetes 46:1733–1742PubMed Tiedge M, Lortz S, Drinkgern J, Lenzen S (1997) Relation between antioxidant enzyme gene expression and antioxidative defense status of insulin-producing cells. Diabetes 46:1733–1742PubMed
10.
Zurück zum Zitat Gurgul E, Lortz S, Tiedge M, Jörns A, Lenzen S (2004) Mitochondrial catalase overexpression protects insulin-producing cells against toxicity of reactive oxygen species and proinflammatory cytokines. Diabetes 53:2271–2280PubMed Gurgul E, Lortz S, Tiedge M, Jörns A, Lenzen S (2004) Mitochondrial catalase overexpression protects insulin-producing cells against toxicity of reactive oxygen species and proinflammatory cytokines. Diabetes 53:2271–2280PubMed
11.
Zurück zum Zitat Azevedo-Martins AK, Lortz S, Lenzen S, Curi R, Eizirik DL, Tiedge M (2003) Improvement of the mitochondrial antioxidant defense status prevents cytokine-induced nuclear factor-kappaB activation in insulin-producing cells. Diabetes 52:93–101PubMed Azevedo-Martins AK, Lortz S, Lenzen S, Curi R, Eizirik DL, Tiedge M (2003) Improvement of the mitochondrial antioxidant defense status prevents cytokine-induced nuclear factor-kappaB activation in insulin-producing cells. Diabetes 52:93–101PubMed
12.
Zurück zum Zitat Forman HJB, Boveris A (1982) Superoxide radical and hydrogen peroxide in mitochondria. In: Pryor WA (ed) Free radicals in biology. Academic, New York, pp 65–90 Forman HJB, Boveris A (1982) Superoxide radical and hydrogen peroxide in mitochondria. In: Pryor WA (ed) Free radicals in biology. Academic, New York, pp 65–90
13.
Zurück zum Zitat Liochev SI, Fridovich I (1994) The role of O2 in the production of HO.: in vitro and in vivo. Free Radic Biol Med 16:29–33CrossRefPubMed Liochev SI, Fridovich I (1994) The role of O2 in the production of HO.: in vitro and in vivo. Free Radic Biol Med 16:29–33CrossRefPubMed
14.
Zurück zum Zitat Tiedge M, Lortz S, Munday R, Lenzen S (1998) Complementary action of antioxidant enzymes in the protection of bioengineered insulin-producing RINm5F cells against the toxicity of reactive oxygen species. Diabetes 47:1578–1585PubMed Tiedge M, Lortz S, Munday R, Lenzen S (1998) Complementary action of antioxidant enzymes in the protection of bioengineered insulin-producing RINm5F cells against the toxicity of reactive oxygen species. Diabetes 47:1578–1585PubMed
15.
Zurück zum Zitat Beck Y, Oren R, Amit B, Levanon A, Gorecki M, Hartman J (1987) Human Mn superoxide dismutase cDNA sequence. Nucleic Acids Res 15:9076PubMed Beck Y, Oren R, Amit B, Levanon A, Gorecki M, Hartman J (1987) Human Mn superoxide dismutase cDNA sequence. Nucleic Acids Res 15:9076PubMed
16.
Zurück zum Zitat Fridovich I (1985) Xanthine oxidase. In: Greenwald RA (ed) Handbook of methods for oxygen radical research. CRC, Boca Raton, FL, pp 51–53 Fridovich I (1985) Xanthine oxidase. In: Greenwald RA (ed) Handbook of methods for oxygen radical research. CRC, Boca Raton, FL, pp 51–53
17.
Zurück zum Zitat Trujillo M, Alvarez MN, Peluffo G, Freeman BA, Radi R (1998) Xanthine oxidase-mediated decomposition of S-nitrosothiols. J Biol Chem 273:7828–7834 Trujillo M, Alvarez MN, Peluffo G, Freeman BA, Radi R (1998) Xanthine oxidase-mediated decomposition of S-nitrosothiols. J Biol Chem 273:7828–7834
18.
Zurück zum Zitat Mosmann T (1983) Rapid colorimetric assay for cellular growth and survival: application to proliferation and cytotoxicity assays. J Immunol Methods 65:55–63CrossRefPubMed Mosmann T (1983) Rapid colorimetric assay for cellular growth and survival: application to proliferation and cytotoxicity assays. J Immunol Methods 65:55–63CrossRefPubMed
19.
Zurück zum Zitat Lortz S, Tiedge M, Nachtwey T, Karlsen AE, Nerup J, Lenzen S (2000) Protection of insulin-producing RINm5F cells against cytokine-mediated toxicity through overexpression of antioxidant enzymes. Diabetes 49:1123–1130PubMed Lortz S, Tiedge M, Nachtwey T, Karlsen AE, Nerup J, Lenzen S (2000) Protection of insulin-producing RINm5F cells against cytokine-mediated toxicity through overexpression of antioxidant enzymes. Diabetes 49:1123–1130PubMed
20.
Zurück zum Zitat Delaney CA, Pavlovic D, Hoorens A, Pipeleers DG, Eizirik DL (1997) Cytokines induce deoxyribonucleic acid strand breaks and apoptosis in human pancreatic islet cells. Endocrinology 138:2610–2614CrossRefPubMed Delaney CA, Pavlovic D, Hoorens A, Pipeleers DG, Eizirik DL (1997) Cytokines induce deoxyribonucleic acid strand breaks and apoptosis in human pancreatic islet cells. Endocrinology 138:2610–2614CrossRefPubMed
21.
Zurück zum Zitat Tiedge M, Lortz S, Munday R, Lenzen S (1999) Protection against the co-operative toxicity of nitric oxide and oxygen free radicals by overexpression of antioxidant enzymes in bioengineered insulin-producing RINm5F cells. Diabetologia 42:849–855CrossRefPubMed Tiedge M, Lortz S, Munday R, Lenzen S (1999) Protection against the co-operative toxicity of nitric oxide and oxygen free radicals by overexpression of antioxidant enzymes in bioengineered insulin-producing RINm5F cells. Diabetologia 42:849–855CrossRefPubMed
22.
Zurück zum Zitat Thor H, Smith MT, Hartzell P, Bellomo G, Jewell SA, Orrenius S (1982) The metabolism of menadione (2-methyl-1,4-naphthoquinone) by isolated hepatocytes. A study of the implications of oxidative stress in intact cells. J Biol Chem 257:12419–12425PubMed Thor H, Smith MT, Hartzell P, Bellomo G, Jewell SA, Orrenius S (1982) The metabolism of menadione (2-methyl-1,4-naphthoquinone) by isolated hepatocytes. A study of the implications of oxidative stress in intact cells. J Biol Chem 257:12419–12425PubMed
23.
Zurück zum Zitat Nakamura M, Hayashi T (1994) One- and two-electron reduction of quinones by rat liver subcellular fractions. J Biochem (Tokyo) 115:1141–1147 Nakamura M, Hayashi T (1994) One- and two-electron reduction of quinones by rat liver subcellular fractions. J Biochem (Tokyo) 115:1141–1147
24.
Zurück zum Zitat Druzhyna NM, Hollensworth SB, Kelley MR, Wilson GL, Ledoux SP (2003) Targeting human 8-oxoguanine glycosylase to mitochondria of oligodendrocytes protects against menadione-induced oxidative stress. Glia 42:370–378CrossRefPubMed Druzhyna NM, Hollensworth SB, Kelley MR, Wilson GL, Ledoux SP (2003) Targeting human 8-oxoguanine glycosylase to mitochondria of oligodendrocytes protects against menadione-induced oxidative stress. Glia 42:370–378CrossRefPubMed
25.
Zurück zum Zitat Lortz S, Tiedge M (2003) Sequential inactivation of reactive oxygen species by combined overexpression of SOD isoforms and catalase in insulin-producing cells. Free Radic Biol Med 34:683–688CrossRefPubMed Lortz S, Tiedge M (2003) Sequential inactivation of reactive oxygen species by combined overexpression of SOD isoforms and catalase in insulin-producing cells. Free Radic Biol Med 34:683–688CrossRefPubMed
26.
Zurück zum Zitat Goossens V, Grooten J, De Vos K, Fiers W (1995) Direct evidence for tumor necrosis factor-induced mitochondrial reactive oxygen intermediates and their involvement in cytotoxicity. Proc Natl Acad Sci U S A 92:8115–8119PubMed Goossens V, Grooten J, De Vos K, Fiers W (1995) Direct evidence for tumor necrosis factor-induced mitochondrial reactive oxygen intermediates and their involvement in cytotoxicity. Proc Natl Acad Sci U S A 92:8115–8119PubMed
27.
Zurück zum Zitat Corda S, Laplace C, Vicaut E, Duranteau J (2001) Rapid reactive oxygen species production by mitochondria in endothelial cells exposed to tumor necrosis factor-alpha is mediated by ceramide. Am J Respir Cell Mol Biol 24:762–768 Corda S, Laplace C, Vicaut E, Duranteau J (2001) Rapid reactive oxygen species production by mitochondria in endothelial cells exposed to tumor necrosis factor-alpha is mediated by ceramide. Am J Respir Cell Mol Biol 24:762–768
28.
Zurück zum Zitat Meier B, Radeke HH, Selle S et al (1989) Human fibroblasts release reactive oxygen species in response to interleukin-1 or tumour necrosis factor-alpha. Biochem J 263:539–545PubMed Meier B, Radeke HH, Selle S et al (1989) Human fibroblasts release reactive oxygen species in response to interleukin-1 or tumour necrosis factor-alpha. Biochem J 263:539–545PubMed
29.
Zurück zum Zitat Schulze-Osthoff K, Beyaert R, Vandevoorde V, Haegeman G, Fiers W (1993) Depletion of the mitochondrial electron transport abrogates the cytotoxic and gene-inductive effects of TNF. EMBO J 12:3095–3104PubMed Schulze-Osthoff K, Beyaert R, Vandevoorde V, Haegeman G, Fiers W (1993) Depletion of the mitochondrial electron transport abrogates the cytotoxic and gene-inductive effects of TNF. EMBO J 12:3095–3104PubMed
30.
Zurück zum Zitat Wenk J, Brenneisen P, Wlaschek M et al (1999) Stable overexpression of manganese superoxide dismutase in mitochondria identifies hydrogen peroxide as a major oxidant in the AP-1-mediated induction of matrix-degrading metalloprotease-1. J Biol Chem 274:25869–25876 Wenk J, Brenneisen P, Wlaschek M et al (1999) Stable overexpression of manganese superoxide dismutase in mitochondria identifies hydrogen peroxide as a major oxidant in the AP-1-mediated induction of matrix-degrading metalloprotease-1. J Biol Chem 274:25869–25876
31.
Zurück zum Zitat Ranganathan AC, Nelson KK, Rodriguez AM et al (2001) Manganese superoxide dismutase signals matrix metalloproteinase expression via H2O2-dependent ERK1/2 activation. J Biol Chem 276:14264–14270 Ranganathan AC, Nelson KK, Rodriguez AM et al (2001) Manganese superoxide dismutase signals matrix metalloproteinase expression via H2O2-dependent ERK1/2 activation. J Biol Chem 276:14264–14270
32.
Zurück zum Zitat McArdle A, van der Meulen J, Close GL et al (2004) Role of mitochondrial superoxide dismutase in contraction-induced generation of reactive oxygen species in skeletal muscle extracellular space. Am J Physiol Cell Physiol 286:C1152–C1158CrossRefPubMed McArdle A, van der Meulen J, Close GL et al (2004) Role of mitochondrial superoxide dismutase in contraction-induced generation of reactive oxygen species in skeletal muscle extracellular space. Am J Physiol Cell Physiol 286:C1152–C1158CrossRefPubMed
33.
Zurück zum Zitat Heine C, Tyynela J, Cooper JD et al (2003) Enhanced expression of manganese-dependent superoxide dismutase in human and sheep CLN6 tissues. Biochem J 376:369–376CrossRefPubMed Heine C, Tyynela J, Cooper JD et al (2003) Enhanced expression of manganese-dependent superoxide dismutase in human and sheep CLN6 tissues. Biochem J 376:369–376CrossRefPubMed
34.
Zurück zum Zitat Takada Y, Hachiya M, Park SH, Osawa Y, Ozawa T, Akashi M (2002) Role of reactive oxygen species in cells overexpressing manganese superoxide dismutase: mechanism for induction of radioresistance. Mol Cancer Res 1:137–146 Takada Y, Hachiya M, Park SH, Osawa Y, Ozawa T, Akashi M (2002) Role of reactive oxygen species in cells overexpressing manganese superoxide dismutase: mechanism for induction of radioresistance. Mol Cancer Res 1:137–146
35.
Zurück zum Zitat Kinnula VL, Pietarinen P, Aalto K, Virtanen I, Raivio KO (1995) Mitochondrial superoxide dismutase induction does not protect epithelial cells during oxidant exposure in vitro. Am J Physiol 268:L71–L77PubMed Kinnula VL, Pietarinen P, Aalto K, Virtanen I, Raivio KO (1995) Mitochondrial superoxide dismutase induction does not protect epithelial cells during oxidant exposure in vitro. Am J Physiol 268:L71–L77PubMed
36.
Zurück zum Zitat Borg LA, Eizirik DL (1990) Short-term exposure of rat pancreatic islets to human interleukin-1 beta increases cellular uptake of calcium. Immunol Lett 26:253–258CrossRefPubMed Borg LA, Eizirik DL (1990) Short-term exposure of rat pancreatic islets to human interleukin-1 beta increases cellular uptake of calcium. Immunol Lett 26:253–258CrossRefPubMed
37.
Zurück zum Zitat Cardozo AK, Kruhoffer M, Leeman R, Orntoft T, Eizirik DL (2001) Identification of novel cytokine-induced genes in pancreatic beta-cells by high-density oligonucleotide arrays. Diabetes 50:909–920PubMed Cardozo AK, Kruhoffer M, Leeman R, Orntoft T, Eizirik DL (2001) Identification of novel cytokine-induced genes in pancreatic beta-cells by high-density oligonucleotide arrays. Diabetes 50:909–920PubMed
38.
Zurück zum Zitat Rogers RJ, Monnier JM, Nick HS (2001) Tumor necrosis factor-alpha selectively induces MnSOD expression via mitochondria-to-nucleus signaling, whereas interleukin-1beta utilizes an alternative pathway. J Biol Chem 276:20419–20427 Rogers RJ, Monnier JM, Nick HS (2001) Tumor necrosis factor-alpha selectively induces MnSOD expression via mitochondria-to-nucleus signaling, whereas interleukin-1beta utilizes an alternative pathway. J Biol Chem 276:20419–20427
39.
Zurück zum Zitat Stephanz GB, Gwinner W, Cannon JK, Tisher CC, Nick HS (1996) Heat-aggregated IgG and interleukin-1-beta stimulate manganese superoxide dismutase in mesangial cells. Exp Nephrol 4:151–158PubMed Stephanz GB, Gwinner W, Cannon JK, Tisher CC, Nick HS (1996) Heat-aggregated IgG and interleukin-1-beta stimulate manganese superoxide dismutase in mesangial cells. Exp Nephrol 4:151–158PubMed
40.
Zurück zum Zitat Sigfrid LA, Cunningham JM, Beeharry N et al (2003) Cytokines and nitric oxide inhibit the enzyme activity of catalase but not its protein or mRNA expression in insulin-producing cells. J Mol Endocrinol 31:509–518CrossRefPubMed Sigfrid LA, Cunningham JM, Beeharry N et al (2003) Cytokines and nitric oxide inhibit the enzyme activity of catalase but not its protein or mRNA expression in insulin-producing cells. J Mol Endocrinol 31:509–518CrossRefPubMed
41.
Zurück zum Zitat Sparre T, Christensen UB, Mose Larsen P et al (2002) IL-1beta induced protein changes in diabetes prone BB rat Islets of Langerhans identified by proteome analysis. Diabetologia 45:1550–1561CrossRefPubMed Sparre T, Christensen UB, Mose Larsen P et al (2002) IL-1beta induced protein changes in diabetes prone BB rat Islets of Langerhans identified by proteome analysis. Diabetologia 45:1550–1561CrossRefPubMed
Metadaten
Titel
Importance of mitochondrial superoxide dismutase expression in insulin-producing cells for the toxicity of reactive oxygen species and proinflammatory cytokines
verfasst von
S. Lortz
E. Gurgul-Convey
S. Lenzen
M. Tiedge
Publikationsdatum
01.08.2005
Erschienen in
Diabetologia / Ausgabe 8/2005
Print ISSN: 0012-186X
Elektronische ISSN: 1432-0428
DOI
https://doi.org/10.1007/s00125-005-1822-3

Weitere Artikel der Ausgabe 8/2005

Diabetologia 8/2005 Zur Ausgabe

Leitlinien kompakt für die Innere Medizin

Mit medbee Pocketcards sicher entscheiden.

Seit 2022 gehört die medbee GmbH zum Springer Medizin Verlag

Positiver FIT: Die Ursache liegt nicht immer im Dickdarm

27.05.2024 Blut im Stuhl Nachrichten

Immunchemischer Stuhltest positiv, Koloskopie negativ – in solchen Fällen kann die Blutungsquelle auch weiter proximal sitzen. Ein Forschungsteam hat nachgesehen, wie häufig und in welchen Lokalisationen das der Fall ist.

GLP-1-Agonisten können Fortschreiten diabetischer Retinopathie begünstigen

24.05.2024 Diabetische Retinopathie Nachrichten

Möglicherweise hängt es von der Art der Diabetesmedikamente ab, wie hoch das Risiko der Betroffenen ist, dass sich sehkraftgefährdende Komplikationen verschlimmern.

Mehr Lebenszeit mit Abemaciclib bei fortgeschrittenem Brustkrebs?

24.05.2024 Mammakarzinom Nachrichten

In der MONARCHE-3-Studie lebten Frauen mit fortgeschrittenem Hormonrezeptor-positivem, HER2-negativem Brustkrebs länger, wenn sie zusätzlich zu einem nicht steroidalen Aromatasehemmer mit Abemaciclib behandelt wurden; allerdings verfehlte der numerische Zugewinn die statistische Signifikanz.

ADT zur Radiatio nach Prostatektomie: Wenn, dann wohl länger

24.05.2024 Prostatakarzinom Nachrichten

Welchen Nutzen es trägt, wenn die Strahlentherapie nach radikaler Prostatektomie um eine Androgendeprivation ergänzt wird, hat die RADICALS-HD-Studie untersucht. Nun liegen die Ergebnisse vor. Sie sprechen für länger dauernden Hormonentzug.

Update Innere Medizin

Bestellen Sie unseren Fach-Newsletter und bleiben Sie gut informiert.