Staff

Prof. Dr. Bernhard Michalke
Deputy Head

Phone: +49 89 3187 4206
E-mail
Building/Room: 22 / 017

 

Bernhard Michalke is head of the group Element- and Element Species

Research Interests:
Trace element determination for diagnosis and therapy control.
Method developments, especially hyphenated techniques for speciation projects (also from the general analytical services).
Trace element speciation in the frame of neurodegeneration research, specifically Manganese- Iron and Selenium speciation in the frame of environmental medicine and neurotoxicology.
Within this field our newly developed CE-ICP-MS method is employed for Iron Redox Speciation of Ferritin, Fe2+ and Fe3+, paralleled by GSH/GSSG differentiation, both helping to characterize oxidative stress and helping to explain steps of ferroptosis mechanism. See the video explanation of the method here.

Our new CE-ICP-DRC-MS based method for quantification of ferrous (Fe2+) and ferric (Fe3+-) iron in tissue and body fluids within ca. 300 seconds:

Background: Oxidative stress (OS) plays a crucial role in a number of serious diseases, especially neurodegenerative diseases of the brain, like Alzheimer's or Parkinson´s disease, as well as in cancer and diabetes (1-6). Oxidative stress is very often related to iron, but not simply to “total iron”, but to the intracellular ratio and balance of the redox couple Fe2+ and Fe3+. While Fe3+ is redox-inactive, reactive oxygen species (ROS) are a direct reaction product of the free Fe2+ ions. Bivalent iron ions (Fe2+) catalyze H2O2 cleavage, being accompanied by the production of hydroxyl radicals, which in turn leads to membrane lipid peroxidation (7,8).

While on the one hand there is a "stable" iron pool in the cells in which iron - mostly Fe3+ - is bound in thermodynamically stable complexes (for example metal chaperones), on the other hand there is a "labile" iron pool as loosely bound, cytoplasmic Fe2+, which easily can be released and is then involved in numerous redox reactions.

At the molecular level, Fe2+-generated ROS and peroxidized phospholipids have a high damaging potential to proteins, lipids and DNA (9,10), resulting even in a programmed necrotic cell death, known as "ferroptosis” (FPT) (11 , 12). Therefore, the quantitative determination of Fe2+ and Fe3+  - i.e. the quantitative iron redox speciation - is of outstanding importance in a broad spectrum of redox-related diseases.

The new CE-ICP-DRC-MS method: Already in 2014 (13) and 2017 (10) the working group “Elements and Element Speciation” under Bernhard Michalke initially developed an LC-ICP-MS based method for iron redox speciation. Although the method works very reliably, it was associated with a higher expenditure of time and material costs. Since capillary electrophoresis (CE) - also coupled to ICP-MS - is often used in the working group, it was logical to develop a fast and reliable, but cheaper method based on CE-ICP-MS coupling (14, 15). The method was first tested on cerebrospinal fluid samples from our research projects on Parkinsonism.

To expand the sample spectrum to other sample types such as cell lysates, our cooperation partner Dr. Vivek Venkataramani from the University of Göttingen (https://pathologie.umg.eu/forschung/redoxmetabolismus-in-tumoren-und-neuronen/) developed a specifically adapted sample preparation technique, where, among other things, the redox equilibrium is not disturbed during sample processing. In this joint cooperation already a series of various cell lysates from different research approaches were successfully operated together with Dr. Vivek Venkataramani. Now, further studies are planned that will show whether quantitative Fe2+ and Fe3+ determinations in biological samples (cell lysates, liquor, tumor samples) can provide information about the extent of Fe2+-mediated tissue damage (biomarkers for "tissue at risk “).

 

Figure: Electropherogram of Fe2+ and Fe3+ - analysis from an SH-SY5Y cell lysate sample (reproduced from 14).

Referenzen

1 Hare, D. J., M. Arora, N. L. Jenkins, D. I. Finkelstein, P. A. Doble, A. I. Bush. Is early-life iron exposure critical in neurodegeneration? Nat Rev Neurol. 11(9), 536-544 (2015).

2 Ashraf, A., M. Clark, P. W. So. The Aging of Iron Man. Frontiers in Aging Neuroscience. 10. doi.org/10.3389/fnagi.2018.00065 (2018).

3 Hare, D. J., Cardoso, B. R., Szymlek-Gay, E. A., Biggs B. A. Neurological effects of iron supplementation in infancy: finding the balance between health and harm in iron-replete infants. Lancet Child Adolesc Health. 2(2), 144-156 (2018).

4 Torti, S. V., Torti, F.M. Iron and cancer: more ore to be mined. Nat Rev Cancer. 13(5), 342–355 (2013).      

5. Asmat, U., Abad, K., Ismail, K. Diabetes mellitus and oxidative stress—A concise review. Saudi Pharm J. 24(5): 547–553 (2016); doi: 10.1016/j.jsps.2015.03.013

6. Giacco, F., Brownlee, M. Oxidative stress and diabetic complications. Circ Res. 107(9): 1058–1070 (2010). doi: 10.1161/CIRCRESAHA.110.223545

7. Kehrer, J. P. The Haber-Weiss reaction and mechanisms of toxicity. Toxicology. 149(1), 43-50 (2000).

8. Gaschler, M. M., Stockwell B. R. Lipid peroxidation in cell death. Biochemical and Biophysical Research Communications. 482(3), 419-425 (2017).

9. Michalke, B., Halbach S., Nischwitz V. JEM Spotlight: Metal speciation related to neurotoxicity in humans. Journal of Environmental Monitoring. 11(5), 939-954 (2009).

10.https://www.helmholtz-muenchen.de/Solovyev, N., Vinceti, M., Grill, P., Mandrioli J., Michalke B. Redox speciation of iron, manganese, and copper in cerebrospinal fluid by strong cation exchange chromatography - sector field inductively coupled plasma mass spectrometry. Anal Chim Acta. 973, 25-33 (2017).

11. Dixon, S. J., Lemberg, K. M., Lamprecht, M. R., Skouta, R., Zaitsev, E. M., Gleason, C. E.,. Patel, D. N, Bauer, A. J., Cantley, A. M., Yang, W. S., Morrison, B., Stockwell, B. R. Ferroptosis: an iron-dependent form of nonapoptotic cell death. Cell. 149(5), 1060-1072 (2012).

12. Stockwell, B. R., Friedmann, Angeli J. P., Bayir, H., Bush, A. I., Conrad, M., Dixon, S. J., Fulda, S., Gascón, S., Hatzios, S. K., Kagan, V. E., Noel, K., Jiang, X., Linkermann, A., Murphy, M. E., Overholtzer, M., Oyagi, A., Pagnussat, G. C., Park, J., Ran, Q., Rosenfeld, C. S., Salnikow, K., Tang, D., Torti, F. M., Torti, S. V., Toyokuni, S., Woerpel, K. A., Zhang, D. D. Ferroptosis: A Regulated Cell Death Nexus Linking Metabolism, Redox Biology, and Disease. Cell. 171(2), 273-285 (2017).

13. Fernsebner, K.., Zorn, J., Kanawati, B., Walker A., Michalke, B. Manganese leads to an increase in markers of oxidative stress as well as to a shift in the ratio of Fe(II)/(III) in rat brain tissue. Metallomics 6(4): 921-931 (2014).

14. Michalke, B., Willkommen, D., Venkataramani V. Iron Redox Speciation Analysis Using Capillary Electrophoresis coupled to Inductively Coupled Plasma Mass Spectrometry (CE-ICP-MS) Frontiers in Chemistry, Vol. 7, article 136 (2019). doi: 10.3389/fchem.2019.00136

15. Michalke, B., Willkommen, D., Venkataramani, V. Quantification of iron redox species (Fe(II), Fe(III)) by capillary electrophoresis - inductively coupled plasma mass spectrometry (CE-ICP-MS), Jove-Journal of Visualized Experiments, 159 (2020)

Memberships:

  • Federation of European Societies on Trace Elements and Minerals:
    President 2007 - 2016

  • German Society of Minerals and Trace Elements:
    Head of Advisory Board 2016 - today
    President 2004 - 2016
    Vicepresident 2000 - 2004

  • Expert group “Analysen in biologischen Materialien” of the „Deutsche Forschungsgemeinschaft DFG“

  • Expert group “BMU/UBA/VCI-Human Biomonitoring” of the „Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit“

  • Senatskommission zur „Prüfung gesundheitsschädlicher Arbeitsstoffe“ of the Deutsche Forschungsgemeinschaft DFG

  • Scientific Conference Boards:
    • International Conference on Trace Element Speciation in Biomedical, Nutritional & Environmental Sciences
    • International Symposium on Metal Ions in Biology and Medicine
    • International FESTEM Symposium on Trace Elements and Minerals in Medicine and Biology
    • International Conference Instrumental Methods and Analysis
    • Trace Elements in Man
  • Editorial Boards:
    • Journal of Environmental Monitoring
    • Journal of Trace Elements in Medicine and Biology
  • Fellow of the Royal Society of Chemistry

 

Organisation of congresses:

  • International Conference on Trace Element Speciation in Biomedical, Nutritional and Environmental Sciences: May 1998, May 2001, May 2004, May 2008, Neuherberg, Germany.
  • 2nd International FESTEM symposium on Trace Elements and Minerals in Medicine and Biology May 2004, Neuherberg
  • Jahrestagung der Gesellschaft für Mineralstoffe und Spurenelemente e.V, May 2004

Publications: