Projects


Walnuts for a healthy brain aging (WalNutA²)

Aims:

This study aims to tests the overall hypothesis: A feed supplemented with walnuts in combination with cognitive and physical activity (WalNutA²) supports healthy aging by improving motor, cognitive, and mitochondrial function in a mouse model of brain aging.  Motor and cognitive functions will be measured using behavioral tests. Mitochondrial function will be assessed using state of the art techniques including ATP levels, mitochondrial respiration and oxidative stress.

Supported by:

CA Walnuts Logo Color Yell 81717 Final v2


Background: 
 It is proposed that WalNutA2 reduces age-related cognitive and motor impairment in aged mice as assessed by neurobehavioral and motor testing including assessment of working memory. Enhanced neuronal plasticity might be one of the underlying mechanisms that will be monitored by measuring synaptic marker proteins and the determination of BDNF levels. A detailed examination of relevant pathways including neuroinflammation using qRT-PCR will enlighten the molecular basis for the beneficial effects of Walnut nutrients in combination with enriched environment and voluntary wheel running in brain aging.

Links:

References:

Hericium erinaceus - a mushroom against neurodegenerative diseases

Background:

Hericium erinaceus is a kind of metabolic syndrome regulator and tonic drug in Chinese Medicine. Fungi of the class of basidiomycetes are known to form a broad spectrum of biologically active secondary metabolites, especially low molecular weight terpenoids. Erinacines, seldom cyathane type diterpenoids, are produced in submerged grown mycelia and fruiting bodies of Hericium erinaceus. Erinacines have been reported to promote nerve growth factor (NGF) synthesis, which suggests the application of H. erinaceus or secondary metabolites derived thereof for the treatment and prevention of dementia and further neural degenerative diseases. H. erinaceus is part of the traditional Chinese Medicine and has and has proved efficacy in models of Alzheimer`s disease and in a human trial to delay cognitive decline in the elderly. 

Aims:

Prof. Zorn`s lab will produce H. erinaceus and will isolated & analyse its metabolites. The potential of erinacines to improve mitochondrial function will be tested in the group of Prof. Eckert using different cell models of AD (HEK-APPsw cells, SH-SY5Y-APP cells, aged NMRI mice). After screening of 12 erinacines 3 hit compounds will be identified. The most efficient erinacine (lead substance) will be further tested in animal models of aging (aged NMRI mice, Prof. Eckert`s lab) and AD (APP/PS1 mice, Prof. Chen`s lab) whether they can improve cognition and mitochondrial function in the brain. Furthermore, the effects on AD pathology will be tested in APP/PS1 mice. 

Supported by:


Groups involved: 

Prof. Dr. Gunter P. Eckert, Nutriton in Prevention & Therapy, JLU Giessen (PI)
Prof. Dr. Holger Zorn, Food chemistry & Food Biotechnology, JLU Giessen. 
Prof. Dr. Sawou Cheng, Traditional Chinese Medicine, Hunan University, Changsha, China.

Links:

References:

PolEnEx - Polyphenols, Enriched Environment, and Exercise

Aims:

The aim of this project is to  test the overall hypothesis: A combination of a diet supplemented with polyphenols, enriched environment, and exercise (PolEnEx) provides healthy aging by improving mitochondrial function in mouse models of aging and AD. Specific aims to be addressed are: (1) PolEnEx attenuates physical and cognitive decline. (2) PolEnEx improves mitochondrial dysfunction in the brain (3) Evaluation of molecular mechanisms underlying PolEnEx. The project is supported by a reserach award from the Alzheimer Forschung Initiative e.V.

Supported by:

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Background: 
Aging of the brain is characterized by a decline in several physiological abilities, including sensory, motor and cognitive functions. Physiological changes that occur during the normal aging of the brain may be exacerbated in vulnerable populations of neurons, initiating pathological processes that finally lead to neurodegenerative disorders, especially to Alzheimer. Increasing evidence suggests that mitochondrial dysfunction plays an important role in brain aging and in the pathogenesis of neurodegenerative diseases. Epidemiological and clinical studies identified the Mediterranean diet together with an active life-style as a promising approach for healthy aging and the prevention of Alzheimer`s disease. Components of the Mediterranean diet, especially grape and olive polyphenols are promising nutraceuticals in the brain and might contribute to the prevention from Alzheimer`s disease. Several preclinical studies reported that polyphenols, exercise and enriched environment counteract declining cognitive functions in aging and AD. Polyphenols, exercise and enriched environment have also been related to improved mitochondrial function in the brain. However, it has not been tested yet if a combination of a diet supplemented with polyphenols, exercise, and enriched environment synergistically counteracts mitochondrial dysfunction in the brain according to the concept of healthy aging for the prevention of AD.

Links:
Alzheimer Forschung Initiative e.v. (AFI) 

References:
Asseburg H, Schaefer C, Mueller M, Hagl S, Pohland M, Berressem D, Borchielline, M, Plank C, Eckert GP
Effects of grape skin extract on age-related mitochondrial dysfunction, memory and life span in C57BL/6J mice
NeuroMolecular Med, 2016, 18(3):378-95. [Pubmed Abstract]

Hagl S, Asseburg H, Eckert GP
Nutritional approaches for healthy aging of the brain and the prevention of neurodegenerative diseases

In: Pharma Nutrition - An Overview (Eds. Garssen, J; Folkerts G), Springer, Stuttgart, 2014, ISBN 978-3-319-06150-4




NeurOliv - Olive Polyphenols for the Prevention of Dementia

Aims:

  • De novo synthesis of functional ingredients from olives
  • Identifying coding genes and use of new synthetic routes to the model of the olive plant
  • Development of efficient downstream processes for the isolation of substances in high purity to preparative scale.
  • Studies of metabolic and biofunctional properties of olive ingredients  in cell and mouse models of Alzheimer's disease in terms of their mitochondrial protective effects.

Supported by:

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Background
Recent clinical studies indicate that certain dietary patterns including the Mediterranean diet may prevent from Alzheimer`s disease. Olives and its products are one key component of the Mediterranean diet. We have shown that olive polyphenols, e.g. hydroxytyrosol, protects from oxidative- and nitrosative stress and improves mitochondrial function in vivo and in vitro. In the new project we will screen a variety of olive ingredients for their potential to improve mitochondrial function in vitro. The best compounds will be further tested for their efficacy in mouse models of brain aging and Alzheimer`s disease.

The special feature of the materials that we are going to test is that they are made by a biotechnological approach. Our partners at the Technical University of Darmsatadt (Prof. Warzecha and his group) develop procedures to produce defined and pure ingredients. Using the genetical informations, bacteria will produce olive compounds in high yields. Starting from this material N-Zyme Biotec GmbH will develop new nutraceuticals and pharmaceuticals for the prevention and treatment of Alzheimer`s  disease. 

References:
Schaffer S, Podstawa M, Visioli F, Bogan P, Müller WE, Eckert GP.
Hydroxytyrosol-rich olive mill waste extract protects brain cells in vitro and ex vivo.
J Agric Food Chem. 2007, 55(13):5043-9.

Schaffer S, Müller WE, Eckert GP.
Cytoprotective effects of olive mill wastewater extract and its main constituent hydroxytyrosol in PC12 cells.
Pharmacol Res. 2010, 62: 322–327.

Links:

N-Zyme Biotec GmbH
TU Darmstadt (Prof. Warzecha and team)


Press & Media:

Press release Goethe-University Frankfurt
Radio-Broadcast HR4, 17.03.2015 [in German]; Oliven gegen das Vergessen []
TV-Broadcast „RTL Hessen“ 29.06.2015; [in German]; Oliven gegen Alzheimer []



Multi-modulators of PPARγ, γ-secretase, and mitochondrial function

Currently approved drugs for the treatment of Alzheimer`s disease (AD) act merely symptomatic and the progression of the disease is delayed for a relative short time period and most if not all new therapeutic approaches have failed in human clinical trials or already in preclinical development.

In the past years research much efforts were being made to identify new disease-modulating agents. In frame of the current project a novel class of dual PPARγ- (peroxisome proliferator-activated receptor γ) and γ-secretase modulators (GSM) to improve mitochondrial dysfunction in AD are developed. After synthesis the compounds are tested in human HEK293-APP695 cells and in mouse models of AD. Chemical modifications should increase the pharmacological potency of the synthesized GSM. Developed GSM so far don`t affect the physiological role of the γ-secretase especially in the Notch signaling pathway, but shift the processing of APP towards Aβ1-38(-40) which is less toxic compared to Aβ1-42. GSM also activate PPARγ. This nuclear receptor represents an important regulator of the lipid and glucose homeostasis, which is impaired in AD. Moreover, GSM improve mitochondrial function e.g. improve mitochondrial membrane potential and ATP levels. 

This project is supported by the Doktor Robert Pfleger-Stiftung and is carried out by Ph. D. student Maximilian Pohland in cooperation with Dr. Mario Wurglics and Prof. Manfred Schubert-Zsilavecz, Goethe-University of Frankfurt.

References

Pohland M, Pellowska M, Asseburg H, Hagl S, Reutzel M, Joppe A, Berressem D, Eckert SH, Wurglics M, Schubert-Zsilavecz M, Eckert GP.
MH84 improves mitochondrial dysfunction in a mouse model of early Alzheimer’s 

Alzheimers Res Ther, 2018; in press

Pohland M, Hagl S, Pellowska M, Wurglics M, Schubert-Zsilavecz M, Eckert GP
MH84 - A novel γ-secretase modulator/PPARγ agonist - improves mitochondrial dysfunction in a cellular model of Alzheimer's disease
Neurochem Res, 2016, 41(1-2):231-42. [Pubmed Abstract]

Pellowska M, Stein C, Pohland M, Merk D, Klein J, Eckert GP, Schubert-Zsilavecz M, Wurglics M. Pharmacokinetic properties of MH84, a γ-secretase modulator with PPARγ agonistic activity
J Pharm Biomed Anal. 2014, 102C:417-424. [Pubmed Abstract]


Prenylation of Rho proteins - impact for neurodegeneration

Rac1

Isoprenoids and certain small Rho GTPases have been implicated in brain aging and neurodegenerative disorders in which current treatment options have been ineffective. Small Rho-GTPases are key regulators in neurogenesis, synapse formation and neuronal differentiation. Post-translational prenylation of small GTPases via transferases (FTase and GGTase I) is important for their localization in membranes, the site of their activation and function. Recent findings showed that regulation of the brain isoprenoids farnesyl (FPP)- and geranylgeranylpyrophosphate (GGPP) is altered in Alzheimer patients (Neurobiol Dis. 2009;35(2):251-7). Since Alzheimer`s disease is strongly associated with aging we tested herein the impact of aging on levels of the mevalonate pathway intermediates FPP and GGPP; levels of total and prenylated small Rho-GTPases; mRNA, protein and activity of GGTase I in cerebrum homogenates of young (2-months) and aged (23-months) C57/BJ6 mice. FPP and GGPP levels were significantly elevated (Mol Neurobiol. 2012; 46(1): 179-85). Currently, we investigate levels of Rho-GTPases Rac-1, RhoA and cdc42 in different brain fractions, e.g. membrane bound Rho-protein indicates prenylation of the proteins. Further, levels of GGTase I mRNA and protein levels,  Rho-GEF (guanine nucleotide exchange factor) Tiam1,  BDNF, and  TrkB receptor levels as well as synaptic markers are determined. The project is carried out by Ph.D. student Sarah Afshordel in cooperation with Prof. W. Gibson Wood, University of Minnesota, Minnapolis, USA.

References

Marschalek N, Albert F, Afshordel S, Meske V, Eckert GP, Ohm TG.
Geranylgeranyl pyrophosphate is crucial for neuronal survival but has no special role in Purkinje cell degeneration in Niemann Pick type C1 disease.
J Neurochem. 2015, 133(1):153-61

Afshordel S, Wood WG, Igbavboa U, Muller WE, Eckert GP. 
Impaired Geranylgeranyltransferase-I Regulation Reduces Membrane-Associated Rho Protein Levels in Aged Mouse Brain.
J Neurochem. 2014, 129(4):732-42.

Hooff GP, Wood WG, Hyun KJ, Igbavboa U, Ong WY, Muller WE, Eckert GP
Brain Isoprenoids Farnesyl Pyrophosphate and Geranylgeranyl Pyrophosphate are Increased in Aged Mice.
Mol Neurobiol. 2012, 46(1):179-85.

Hooff GP, Peters I, Wood WG, Müller WE, Eckert GP.
Modulation of cholesterol, farnesyl- and geranylgeranylpyrophosphate in neuronal SY5Y cells - impact for beta-amyloid production.
Mol Neurobiol. 2010, 41(2-3):341-50.

Eckert GP, Hooff GP, Igbavboa U, Strandjord DM, Volmer DA, Müller WE, Wood WG. Regulation of brain isoprenoids farnesyl and geranylgeranyl pyrophosphate is altered in male Alzheimer’s disease.
Neurobiol Disease. 2009, 35: 251-7.

Hooff GP, Volmer D, Wood WG, Müller WE, Eckert GP.
Isoprenoid quantitation in human brain tissue. A validated HPLC-fluorescence detection method for endogenous farnesyl- (FPP) and geranylgeranylpyrophosphate (GGPP).
Anal Bioanal Chem. 2008, 392: 673-80.



Monoterpenes against glioma

Alterations in Ras-mediated signal transduction emerged as a central step in the molecular pathogenesis of high-grade glioblastoma multiforme (GBM). Prenylation of H-Ras by farnesylpyrophosphate (FPP) is required for membrane insertion and facilitated by farnesyltransferase (FTase). FPP is derived from mevalonate, whose production is catalyzed by HMG-CoA reductase (HMGR), which is the rate limiting step of the mevalonate/isoprenoid/cholesterol-(MVA) pathway. Post-translational modification of H-Ras is essential for its oncogenic function, e.g. the stimulation of the mitogen-activated protein kinase (MAPK) pathway. A straight forward prediction from HMGR inhibitor studies would be that FPP levels could be diminished by lovastatin. This assumption, however, has not been tested, and the lack of such data is in stark contrast to the important role of isoprenoids in protein prenylation and oncogenic function. Here, we examine the effects of lovastatin (LOV) and perillyl alcohol (POH) in human malignant astrocytoma cell lines U87 and U343. Human astrocytes (HA) served as controls. Paramters under investigation: Levels of H-Ras, Rac1, RhoA and cdc42 in cell homogenate, cytosolic and membrane fractions, cellular levels of FPP, GGPP and cholesterol, levels of pERK1/2 and ERK1/2, cell proliferation, migration and invasion. The project is carried out by Ph.D. student Sarah Afshordel.

References

Afshordel S, Kern B, Clasohm J, König H, Priester M, Weissenberger J, Kögel D, Eckert GP
Lovastatin and Perillyl alcohol Inhibit Glioma Cell Invasion, Migration, and Proliferation – Impact of Ras-/Rho- Prenylation
Pharmacol Res. 2015, 91:69-77

Flavones for improved synaptic plasticity

Brain-derived neurotrophic factor (BDNF) is a cognate ligand for the tyrosine kinase receptor B (TrkB) receptor and thus mediates neuronal differentiation and survival, synaptic plasticity and neurogenesis. 

The therapeutic potential of BDNF is limited by its poor pharmacokinetic profile. 7,8-dihydroxyflavone (7,8 DHF) is a bioactive high-affinity TrkB agonist that provokes receptor dimerization, autophosphorylation and activation of downstream signaling.

7,8-DHF is a member of the flavonoid family, that has been demonstrated to rescue in vitro long-term synaptic plasticity in the hippocampus of aged rats and in vivo rescues aging-related cognitive impairment in rats (Journal of Neurochemistry, 122: 800–811, 2012). 

The neurotrophic effects of 7,8-DHF have been identified in various neurological diseases such as ischemic stroke and Parkinson’s disease. 7,8-DHF protected wild-type, but not TrkB-deficient, neurons from apoptosis  and administration of 7,8-DHF to mice activated TrkB in the brain, inhibited kainic acid-induced toxicity, decreased infarct volumes in stroke in a TrkB dependent manner, and was neuroprotective in an animal model of Parkinson disease (Sung-Wuk Jang et al., PNAS, 107.6: 2687–2692, 2010). 

The angiogeneic effect of 7,8-DHF has been observed in endothelial cells derived from resistance vessel of the brain. Angiogenesis by 7,8-DHF is an important factor that helps prevent and treat various ischemic diseases (Jeremy Williams et al., 2011).

The neurotrophin brain-derived neurotrophic factor (BDNF) and its receptor tropomyosin-related kinase B (TrkB) have also emerged as mediators in the pathophysiology of post-traumatic stress disorder, where patients show cognitive deficits. In this context, 7,8-DHF blocks long-term spatial memory impairment caused by immobilization stress in rats hippocampus (Andero et al., hippocampus, 22: 399–408, 2012).

It has also been shown that 7,8-DHF exhibits therapeutic efficacy in a mouse model of Rett syndrome (Johnson et al., Journal of Applied Physiology, 112: 704–710, 2012).

Increasing evidence suggests that reductions in brain-derived neurotrophic factor (BDNF) and its receptor tyrosine receptor kinase B (TrkB) may have a role in the pathogenesis of Alzheimer’s disease (AD). 7,8-DHF reverses memory deficits and BACE1 elevation in a mouse model of Alzheimer’s Disease (Latha Devi and Masuo Ohno, Neuropsychopharmacology 37: 434–444, 2012).

Thus, 7,8-dihydroxyflavone imitates BDNF and acts as a robust TrkB agonist, providing a powerful therapeutic tool for the treatment of various neurological diseases. Current findings about 7,8-DHF and other functional mimetics of BDNF could evolve into a new class of drugs for cognitive aging and aging-related neurodegenerative diseases. The project is carried out by Ph.D. student Sarah Afshordel in cooperation with Prof. W. Gibson Wood, University of Minnesota, Minnapolis, USA.


Billberry extract for brain protection

The objective of this joint research project (Sabine Kuntz, Gießen; Gunter Eckert, Frankfurt) is to test the effects of a standardized encapsulated bilberry extract (BE) on biomarkers such as oxidative and inflammatory parameters, which are both targeting directly mitochondria and lead to mitochondrial dysfunctions. Neuronal PC12 cells, mouse models of aging and Alzheimer`s disease (senescence-accelerated prone mice (SAMP) and C57BJ/6-Thy1-APP751SL) and a human intervention trial with aged volunteers should prove efficacy of BE on markers of mitochondrial function and inflammation in lymphocytes and dissociated brain cells ex vivo. The simultaneous investigation of brain cells and lymphocytes from our mouse models as well as lymphocytes from the intervention trail represents an innovative approach that may finally allow to draw conclusions from processes in the human brain, although this organ is not assessable for biochemical investigations. Our preliminary data show beneficial effects on oxidative parameters in the blood of young and healthy volunteers after ingestion of an anthocyanin-rich beverage over 14 d interventions. A considerable amount of studies assessed the possible mechanisms of anthocyanin action including their interaction with signaling pathways. However, there is scarce information about the impact on mitochondrial function. Our preliminary data show that anthocyanin-rich bilberry extract protects neuronal PC12 cells from nitrosative stress induced mitochondrial dysfunction.  The evaluation of molecular mechanisms will focus on the induction of endogenous protective mechanisms, e.g. enhanced gene and protein expression of PGC1α, PPARγ, CREB, Nrf2/Keap1 or NF-κB/STAT and may identify new links between mitochondrial dysfunction, oxidative stress and inflammation. Identified targets of BE will be validated using specific inhibitors and siRNA approaches in vitro, leading to new strategies for disease prevention (funding is currently pending) . The project is carried out by Ph.D. student Heike Asseburg in cooperation with Dr. Sabine Kuntz and Prof. Clemens Kunz, Justus-Liebig University, Gießen, Germany.

Omega-3-fatty acids for a healthy brain

fetterFisch

Strategies for long-term prevention from mitochondrial dysfunction including  sufficient supply of essential nutrients may also delay the onset of age-related neurodegenerative diseases. The present project investigates the effects of orally administered DHA- and EPA-rich fish oil (FO) on mitochondrial function in brains of young (3 months) and aged (24 months) NMRI-mice. Neuroprotective properties of FO are assessed ex vivo after 21 days in dissociated brain cells (DBC) and isolated mitochondria (mito). DHA levels are determined in blood and in brain tissue of mice. Isolated ATP levels, mitochondrial membrane potential and respiration are detemined in DBC and brain mitochondria, respectively. Recent data identified DHA-mediated increases in sAPPalpha, which were associated with protection of mitochondrial function in vitro (BBA 1808(2011)236). Accordingly, we currently investigate if sAPPalpha and/or DHA-derived metabolites such as NPD-1 are responsible for the observed beneficial effects of FO against age-related mitochondrial dysfunction in vivo. Our findings will provide new mechanisms underlying the neuroprotective actions of polyunsaturated fatty acids and identified FO as promising neutraceutical to delay age-related
cerebral alterations. Recently, we extended our portfolio and investigate the beneficial effects of fish oil for ischemic stroke using a MCAO mouse model. The project is carried out by Ph.D. student Dirk Berresem.

References:

Ostermann AI, Reutzel M, Hartung N, Franke N,  Kutzner L, Schoenfeld K, Weylandt KH, Eckert GP, Schebb NH.
A Diet Rich in Omega-3 Fatty Acids Enhances Expression of Soluble Epoxide Hydrolase in Murine Brain.
Prostaglandins Other Lipid Mediat. 2017; S1098-8823(17)30043-6. [Pubmed Abstract]

Berressem D, Koch K, Franke N, Klein J, Eckert GP.
Intravenous treatment with a long-chain omega-3 lipid emulsion provides neuroprotection in a murine model of ischemic stroke - a pilot study.
PLoS ONE, 2016;11(11):e0167329. [Open access]

Afshordel S, Hagl S, Werner D, Rohner N, Kogel D, Bazan N, Eckert GP
Omega-3 Polyunsaturated Fatty Acids improve mitochondrial dysfunction in brain aging - impact of Bcl-2 and NPD-1 like metabolites
Prostaglandins Leukot Essent Fatty Acids. 2015, 92:23-31 [Pubmed Abstract]

Eckert GP, Lipka U, Muller WE.
Omega-3 fatty acids in neurodegenerative diseases: Focus on mitochondria
Prostaglandins Leukot Essent Fatty acids, 2013, 45(1):76-80. [Pubmed Abstract]

Eckert GP, Chang S, Eckmann J, Copanaki E, Hagl S, Hener U, Müller WE, Kögel D.
Liposome-incorporated DHA increases neuronal survival by enhancing non-amyloidogenic APP processing. 
Biochim Biophys Acta. 2011, 1808(1):236-43. [Open access]




© Prof. Dr. Gunter P. Eckert 2018