Environmental Exposure Impact

CHEM: Environmental Exposure Impact / Metallomics & Metabolomics

The mean research axis at BGC in the field of chemical impact of environmental exposures are related to the effect of various metals (contact, air or food) on human health and is reflected in the research group of Prof. B. Michalke with a focus on diabetes and neurodegeneration research. The combination of metallomics and metabolomics enables two fields of investigation:

(i) Parkinsonian like disorders

We investigate two different types of Parkinsonian disorders: Manganese (Mn) dependent Parkinsonism and idiopathic Parkinsonism.

Mn-dependent Parkinsonism: Manganese (Mn) is important for the functionality of various physiological processes. It is not only involved in protection of cells against oxidative stress but also in synthesis and metabolism of neurotransmitters. Therefore, an overexposure to this trace element can lead to a neurological disorder termed manganism, mainly observed in occupationally exposed people. The symptoms of this disease are similar to Parkinson Disease and ongoing mechanisms in the affected brain are investigated.
The project aimed to clarify in which chemical form Mn is reaching neural barriers. Mn-speciation in serum (before NB) and in CSF (behind NB), notably in paired serum and CSF samples was investigated. Most important findings from these experiments were that under Mn exposure HMM-Mn species did not increase in serum or did even decrease, in contrast to LMM-Mn species, above all Mn-citrate, which were increased. A Mn-citrate complex was identified by 2-D approaches using different speciation methods (metallomics approach) and a key-technique from metabolomics (ESI-FT-ICR-MS). We showed that at slightly elevated total Mn concentration in serum a change in Mn carriers towards Mn-citrate takes place, which is even enriched across neural barriers. Therefore, Mn-Citrate appears to be that important Mn metabolite reaching the brain after Mn exposure.
We further clarified the mechanism of Mn-related neuronal damage. Mn exposure altered the Fe metabolism in brain. The total Fe concentration was reduced and the important homeostasis of the Fe(III)/Fe(II) ratio was shifted toward Fe(II). This was paralleled by a metabolic change towards oxidative stress in brain. The combination of metabolomics with metallomics revealed that oxidative stress- and inflammation markers as well as lipid peroxidation markers were significantly elevated after Mn exposure. Many metabolic pathways were severely altered. Finally, we monitored changes in the GABAergic system with significant elevation of glutamate concentration and AchE activity. Both effects cause changes of neuronal excitability in basal ganglia. This relationship between neuronal excitability and increase of AchE or glutamate explains the similarity of Mn-dependent symptoms to idiopathic Parkinson disease.

The idiopathic Parkinson´s disease is affecting about 1% of the population above 65 years. The etiology is still incomplete understood, but it is suggested that occupational and environmental exposure to metals like iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn) can influence the risk for Parkinson´s disease. These metals play a key role as cofactors in many enzymes and proteins. In this case-control study, we investigated the Mn-, Fe-, Cu- and Zn-species in cerebrospinal fluid (CSF) again combining metallomics with metabolomics techniques (LC-ICP-MS and ESI-FT-ICR-MS).
Total metal concentration and speciation differentiated insignificantly between cases and controls but specific LMM-metal ratios, notably involving amino acid-fraction of Cu, differentiated significantly the two groups. Overall 20 ratios showed significant differences between case and control. These metallomics studies were completed by an additional metabolomics approach: sPLS-DA analysis of the ESI-FT-ICR-MS data, and even more OPLS-DA analysis, clearly distinguished controls from the Parkinson´s disease patients. 68 metabolites increased from control-samples and 152 metabolites from Parkinson-samples. The most affected compounds derived from fatty acids (decanoic acid, 10-hydroxydecanoic acid, arachidonic acid, dihomo-γ-linolenic acid, diacylglycerol (DG), phosphatidylcholine (PC) and phosphatidylethanolamine (PE)). Additionally sugar derivates and carboxylic acids were affected. Several PD-increased metabolites, e.g. 5-Oxoproline, are associated with oxidative stress. We also found an increased content of DGLA and ARA in CSF of Parkinson´s patients what seems to be associated with an elevation in pro-inflammatory characteristics.

Conclusion: Metallomics, comprising speciation analysis, being combined with metabolomics techniques is a unique and powerful approach to investigate neurodegenerative conditions, which can elucidate detrimental mechanisms on a molecular level.

 

Selected Publications:

Michalke, B. (2016). Review about the manganese speciation project related to neurodegeneration: an analytical chemistry approach to increase the knowledge about manganese related parkinsonian symptoms. Journal of Trace Elements in Medicine and Biology, 37, 50-61.

Michalke, B., Aslanoglou, L., Ochsenkühn-Petropoulou, M., Bergström, B., Berthele, A., Vinceti, M., ... & Lidén, G. (2015). An approach for manganese biomonitoring using a manganese carrier switch in serum from transferrin to citrate at slightly elevated manganese concentration. Journal of Trace Elements in Medicine and Biology, 32, 145-154.

Fernsebner, K., Zorn, J., Kanawati, B., Walker, A., & Michalke, B. (2014). 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.

Neth, K., Lucio, M., Walker, A., Kanawati, B., Zorn, J., Schmitt-Kopplin, P., & Michalke, B. (2015). Diverse serum manganese species affect brain metabolites depending on exposure conditions. Chemical research in toxicology, 28(7), 1434-1442.

Neth, K., Lucio, M., Walker, A., Zorn, J., Schmitt-Kopplin, P., & Michalke, B. (2015). Changes in brain metallome/metabolome pattern due to a single iv injection of manganese in rats. PloS one, 10(9), e0138270.

(ii) Amytrophic lateral sclerosis (ALS)

For ALS project, we investigated hospital-referred cases-control series and advanced speciation methods combined with metabolomics studies. The patient groups were separated into a) sporadically induced ALS, b) genetically caused ALS and c) a retrospective cohort study with 42 months follow-up observing the development of Alzheimer´s Disease (AD from mild cognitive impairment (MCI). We compared the chemical species of selenium and transition metals in cerebrospinal fluid from respective ALS patients to age and gender matched controls.

Results a)
We found that higher concentrations of inorganic selenium in the form of selenite and of human serum albumin-bound selenium, but lower concentrations of selenoprotein P-bound selenium were associa ted with elevated ALS risk. The associations were stronger among cases age 50 years or older. These results suggest that excess selenite and human serum albumin bound-selenium and low levels of selenoprotein P in the central nervous system, may play a role in ALS etiology.

Results b)
In a patient with the tubulin-related TUBA4A mutation, we found highly elevated levels of glutathione-peroxidase-bound selenium (32.8 vs 1.0 μg/l) as well as increased levels of selenoprotein-P-bound selenium (2.4 vs 0.8 μg/l ), selenite (1.8 vs 0.1 μg/l ), and selenate (0.9 vs 0.1 μg/l). In the remaining ALS patients, we detected elevated selenomethionine-bound selenium levels (0.38 vs 0.06 μg/l ).We concluded that selenium compounds can impair tubulin synthesis and cytoskeleton structure, as do tubulin-related genes mutations. The elevated selenium species levels in the TUBA4A-patient may have a genetic etiology and/or represent a pathogenic pathway through which this mutation favors disease onset. The elevated selenomethionine levels in the other patients is of interest due to the toxicity of this non-physiological selenium species. Our findings are the first to assess selenium exposure in genetic ALS, suggesting an interaction between this environmental factor and genetics in triggering disease onset. From this sample set, transition metal speciation and metabolomics results are presently statistically processed and evaluated.

Results c)
From 42 MCI patients at baseline, twenty-one subjects developed Alzheimer’s disease, 4 frontotemporal dementia and 2 Lewy body dementia. Baseline inorganic selenium (particularly in its inorganic hexavalent form, selenate) was inversely correlated with β-amyloid and phosphorylated tau protein levels in cerebrospinal fluid. In a Cox proportional hazards model higher concentrations of total selenium and of selenate were associated with higher risk of conversion to Alzheimer’s disease. Risk was also slightly correlated with selenomethionine-bound selenium, while it showed little departure from unity for the selenium species linked to antioxidant proteins, known to be upregulated by oxidative stress. From those results we conclude that the concentration of potentially toxic selenium species may predict progression from MCI to AD.

 

Selected Publications:

Vinceti, M., Solovyev, N., Mandrioli, J., Crespi, C. M., Bonvicini, F., Arcolin, E., ... & Michalke, B. (2013). Cerebrospinal fluid of newly diagnosed amyotrophic lateral sclerosis patients exhibits abnormal levels of selenium species including elevated selenite. Neurotoxicology, 38, 25-32.

Vinceti, M., Mandrioli, J., Borella, P., Michalke, B., Tsatsakis, A., & Finkelstein, Y. (2014). Selenium neurotoxicity in humans: bridging laboratory and epidemiologic studies. Toxicology letters, 230(2), 295-303.

Vinceti, M., Grill, P., Malagoli, C., Filippini, T., Storani, S., Malavolti, M., & Michalke, B. (2015). Selenium speciation in human serum and its implications for epidemiologic research: a cross-sectional study. Journal of Trace Elements in Medicine and Biology, 31, 1-10.

Mandrioli, J., Michalke, B., Solovyev, N., Grill, P., Violi, F., Lunetta, C., ... & Vinceti, M. (2017). Elevated levels of selenium species in cerebrospinal fluid of amyotrophic lateral sclerosis patients with disease-associated gene mutations. Neurodegenerative Diseases, 17(4-5), 171-180.

Besides these activities involving metallomics, organic profiling (environmental metabolomics) is realized in following fields in a network involving partners at the center and international (see references).

  • Air quality and aerosols (sulfate esters, ship sulfur emissions, biomass burning chemistry)
  • Allergies (NO2-, O3- and UV-affected pollen metabolomes)
  • Drinking water, ballast water and fracking (formation of halogenated disinfection byproducts

 

Selected Pucblications:

Luek, J. L., Schmitt-Kopplin, P., Mouser, P. J., Petty, W. T., Richardson, S. D., & Gonsior, M. (2017). Halogenated Organic Compounds Identified in Hydraulic Fracturing Wastewaters Using Ultrahigh Resolution Mass Spectrometry. Environmental Science & Technology, 51(10), 5377-5385.

Gonsior, M., Mitchelmore, C., Heyes, A., Harir, M., Richardson, S. D., Petty, W. T., ... & Schmitt-Kopplin, P. (2015). Bromination of marine dissolved organic matter following full scale electrochemical ballast water disinfection. Environmental science & technology, 49(15), 9048-9055.

Yassine, M. M., Harir, M., Dabek‐Zlotorzynska, E., & Schmitt‐Kopplin, P. (2014). Structural characterization of organic aerosol using Fourier transform ion cyclotron resonance mass spectrometry: aromaticity equivalent approach. Rapid Communications in Mass Spectrometry, 28(22), 2445-2454.

Gilles, S., Fekete, A., Zhang, X., Beck, I., Blume, C., Ring, J., ... & Traidl-Hoffmann, C. (2011). Pollen metabolome analysis reveals adenosine as a major regulator of dendritic cell–primed T H cell responses. Journal of Allergy and Clinical Immunology, 127(2), 454-461.

Lavonen, E. E., Gonsior, M., Tranvik, L. J., Schmitt-Kopplin, P., & Köhler, S. J. (2013). Selective chlorination of natural organic matter: identification of previously unknown disinfection byproducts. Environmental science & technology, 47(5), 2264-2271.