Projects winter semester 2019/2020

Characterizing the ER stress response in ALS; a novel translational approach using patient-derived leukocytes

Supervisor: PD Dr. Julian Grosskreutz, RG NEDIG, Department for Neurology

Contact: E-Mail, Tel: +49 - 9 323 426

Project decription: Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disease and is characterized by relentless upper and lower motor neuron degeneration. No disease-modifying therapies currently exist, with most patients eventually succumbing to respiratory failure within 2-3 years from symptom onset. Understanding the underlying cellular pathology is crucial for the development of therapeutic targets. The Endoplasmic Reticulum (ER) and Mitochondrial Calcium Cycle (ERMCC) including the mitochondrial calcium uniporter (MCU) and the Sigma-1 Receptor (Sig1R) have been shown to be dysregulated at both the expression and functional level by our own group. In addition, the unfolded protein response (UPR) and autophagy designed to buoy cells against these dysregulations are compromised in ALS. As physiological ageing also blunts the efficiency of these processes, ALS presents as a complex interplay between inherent genetic susceptibility and ageing-associated challenges.

The proposed project aims to dissect ER stress cascades in peripheral blood mononuclear cells (PBMCs) acquired from patients and healthy controls. PBMCs represent a readily accessible cell source that dynamically reflects pathophysiological processes underway in the central nervous system (CNS), thus also capturing the systemic and multi-factorial nature of ALS. Our group has previously used PBMCs from ALS patients and demonstrated persistent pro-inflammatory phenotypes, dysregulated chemokine receptor expression, increased oxidative stress, dysregulated calcium buffering, and most recently, an up-regulation of the UPR component ATF6 that also seems to be affected by age. We now aim to further characterize and dissect these signals, in particular those of specific UPR components in individual patient PBMCs to better understand the effect of both age and disease-state.

All acquired molecular data will be analyzed within the framework of the novel D50 disease progression model which enables quantitative interpretation within the context of both individual disease aggressiveness and relative disease course covered, thus making the proposed work truly translational in scope.

Exploration of age-dependent differentiation capacity of human/murine mesenchymal stem cells

Supervisor: Prof. Dr. Uta Dahmen, RG Experimental Transplantation Surgery, Department for General, Visceral and Vascular Surgery

Contact: E-Mail, Tel: +49 3641 - 9 325 350

Project decription: Stem cells have a high capacity for proliferation and differentiation. Using appropriate culture condition they can be driven to differentiate into the desired cell type in vitro. Therefore stem cells are an important cell type for the repopulation of biological organ scaffolds during the process of organ engineering. However, stem cells are aging like all other cells in the organism. It is unknown to which extent the aging process affects these unique properties.

This project aims for exploring the age dependent properties, especially the proliferative potential and the differentiation power of human and murine stem cells, and how to modulate them.

The candidate should be willing to learn stem cell isolation from human and murine specimen, as well as cell culture, Flowcytometry, immunohistochemistry, protein chemistry and functional assays.

Cardiac mitochondria as mediators of premature ageing with low exercise capacity

Supervisor: Dr. Michael Schwarzer, Department for Cardiac and Thoracic Surgery

Contact: E-Mail, Tel: +49 3641 - 656 805

Project decription: With increasing age, the risk to develop cardiovascular as well as other age related diseases increases. Exercise training has been suggested as a therapeutic intervention to slow age related degeneration and aerobic running capacity correlates best with cardiovascular risk factors and life expectancy. Genetically determined differences in exercise capacity are responsible for part of the observed differences but cannot be assessed in humans. Animals with low exercise capacity present with reduced life span.

Divergent mitochondrial function is associated with differences in aerobic exercise capacity. Furthermore, a decline in mitochondrial function has been described during ageing in muscle and heart. Thus, the goal of this project is to search for mitochondrial mechanisms in the heart that explain the shorter life expectancy in individuals with lower exercise capacity. The results will be important for identifying the underlying mechanisms of the influence of exercise on aging. In this thesis, changes in respiratory chain complex activity will be identified. Such changes may lead to increased reactive oxygen species production which may lead to mitochondrial damage. Changes in signaling cascades on metabolic pathways and mitochondrial maintenance will be investigated. All proposed methods are established in the lab and currently running. The investigation should be able to identify the molecular mechanisms of the influence of aerobic exercise capacity on ageing.

Age-dependent mechanisms of Learning, Unlearning and Relearning

Supervisor: PD Dr. Carsten Klingner, RG Neuroimaging, Biomagnetic Centre, Department for Neurology

Contact: E-Mail

Project decription: A key problem in learning new skills is that they interact with the skills already learned. So it is, for example much more difficult to adapt to the inverted control of a computer game, if you have previously trained the alternative control for many hours. The motor tasks interact with each other. In the area of ​​medical rehabilitation, this phenomenon is even more significant, as "unlearning" of something is a prerequisite to a necessary release of neuronal capacity that is urgently needed for learning an important lost skill.

In this project, we investigate in particular the age-dependence of the ability to de-learn motor skills and to investigate the degree of interaction between already learned de-learned and newly learned skills.

The training paradigm is the learning to 10-finger typewriting. We test the success of learning with a simple performance check of this ability with both a keyboard layout that matches the one learned and a keyboard layout that does not. In the second part of the experiment, the subjects then must train another alternative keyboard design in the 10-finger system. This requires the de-learning of the previous 10 finger system. The target parameters are the interaction of the already learned with the new task — the age dependency of this process and dependence on the basic learning speed.

Besides the behavioral level, we are interested in the underlying mechanism within the brain associated with the interaction and the delearning of motor tasks. The subjects are therefore examined under the motor test condition several times in functional MRI. Here we are interested in the connectivity of the loop of sensorimotor cortex, basal ganglia, and thalamus. In particular, we are interested in the changes that are induced as a result of the de-learning of a motor task.

Unsupervised motor learning in a virtual environment

Supervisor: PD Dr. Stefan Brodoehl, RG Neuroimaging, Biomagnetic Centre, Department for Neurology

Contact: E-Mail

Project decription: Motor learning especially the new-learning and re-learning of movements and procedures is essential in the course of a variety of neurological diseases (i.e. motor stroke). Often, a lesion of the brain is associated with an older age, resulting in decreased effectiveness of motor training rehabilitation.
Motor rehabilitation and physiotherapy is usually not supported by health insurances in chronic stroke patients. For many people with persistent motor disabilities, there are insufficient resources to continue motor rehabilitation training. In addition, currently established methods for motor rehabilitation have essentially developed historically and take little or no account of modern neuroscientific insights concerning brain plasticity and learning research.

Our research group provides a virtual training environment with real-time capture of hand movements and implements these movements into a game-like environment.
The scholarship holder will translate modern learning approaches (such as false feedback, mirror training) into game elements. These elements will be systematically tested for their effectiveness, in particular in regard to age-dependent alterations. Therefore the training environment will be applied to young (20-30yrs) and older subjects (60-75yrs).
The scholarship holder will create and test virtual training scenarios. The effect of the applied techniques will be directly measured within the game environment. Additionally, we will monitor changes in functional and structural brain plasticity using MRI and MEG measurements.

Age-dependent impairment of brain plasticity by microglial aging

Supervisor: Dr. Christian Schmeer, RG Neuroglia, Department for Neurology

Contact: E-Mail, Tel.: +49 3641 - 9 325 828

Project decription: As we age, changes occur in our bodies, including the brain. Changes in the brain can affect mental function, even in healthy older people, and impair the quality of life. Aging is also a major risk factor for most common neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis. The cellular and molecular mechanisms involved in aging-associated changes in the brain are still mostly unknown.

Our study focuses on, the resident immune cells of the brain. These cells are critical for the formation of inflammatory processes. In addition, recent studies have shown that microglia play a crucial role in dendritic spine generation and consequently in cognition. The impact of aging on microglial function is still poorly understood. In a previous study we already showed that microglia undergo age-related changes on both phenotypic (marker expression) and functional (phagocytosis, dendritic growth) levels (Stojiljkovic et al., 2018). We hypothesize that aging induced changes in microglial properties are crucial for the age-associated alterations in brain function. Therefore, our study aims to address changes in the cellular and functional plasticity of the brain as a function of the age-related changes of the microglia. In order to test our hypothesis, we will perform co-culture assays and cell-type specific (microglial) gene expression analyses. We expect this study to contribute to the elucidation of mechanism involved in brain aging.

Role of the nuclear pore complex (NPC) in replicative reprogramming of neurons in the aged and ALS-diseased CNS

Supervisor: Dr. Alexandra Kretz, RG Neurodegeneration and regeneration, Department for Neurology

Contact: E-Mail, Tel.: +49 3641 - 9 323 499

Project decription: Loss of protein homeostasis is fundamental to many age-related neurodegenerative disorders and the aging process itself. One relevant contributor to this process is, apart from altered rates, e.g., in synthesis, turnover and degradation, the decay in the subcellular compartmentalization of proteins. Likewise, disturbed nucleo-cytoplasmic molecule transport has recently been identified to exert an inductive role in the pathobiology of amyotrophic lateral sclerosis (ALS), an age-related incurable disease characterized by the irreversible degeneration of motor neurons. The biochemical gateway for nucleo-cytoplasmic transport of macromolecules is the nuclear envelope and its specialized transport channels.

Goals of the thesis project are: 1. structural and functional characterization of transport processes associated with the nuclear envelope in aged and ALS-diseased neurons; 2. impact of displaced target protein classes on the aging and ALS disease process; 3. re-equilibration of the subcellular target protein content; 4. rescue of the ALS or aging phenotype.

Methodically, transport channels are characterized bio- and histochemically. Data obtained are aligned to pre-existing mass spectrometric datasets. Target proteins are assessed by fluorescence reporter systems. For rescue studies, a pharmacological approach is applied. Studies are performed in animal models for CNS aging and ALS pathology.

The project implements a novel approach to better understand age-related neurodegeneration and offers avenues for putative causal treatment options in ALS, which are currently missing.

Targeting the interaction between plasmacells and microenvironment to treat multiple myeloma

Supervisors: Prof. Dr. Marie von Lilienfeld-Toal, RG Infections in Haematology/Oncology, Department of Hematology and Medical Oncology; Dr. Annamaria Brioli, RG Infections in Haematology/Oncology, Department of Hematology and Medical Oncology

Contact: E-Mail, Tel.: +49 3641 - 9 324 210 (Prof. Dr. Marie von Lilienfeld-Toal)
                E-Mail (Dr. Annamaria Brioli)

Project decription: Multiple myeloma, the second most frequent hematologic malignancy is still nowadays an incurable disease. Multiple myeloma affects mainly the elderly population; the median age at diagnosis is 69 years and 62% of patients are older than 65 years at the time of diagnosis. As the population ages, the prevalence of this still incurable disease is expected to further increase. Aging population is an extremely challenging field for hematologist, as age and comorbidities significantly impact on the possibility to administer anti cancer treatment. Indeed age itself, irrespective of comorbidities, is considered a risk factor that might warrant treatment dose reduction.

Therefore, new and less toxic treatments are urgently needed. In a preliminary screening of an epigenetic library we identified promising compounds that might act synergistically with existing treatments, enabling treatment administration at lower doses with reduced toxicity. The present project should bring this work forward, not only identifying the optimal doses to use in combination treatments with know active anti-myeloma drugs, but should also investigate deeper the mechanism of action of these compounds alone and in combination. Furthermore, as the survival of myeloma cells is known to depend on the interaction between the malignant plasma cells and the microenvironment, the single compounds and combination treatments will be investigated after different co-culture conditions of myeloma plasma cells and stromal cells. Co-culture (normal co-culture, trans well system, conditioned media) will be performed both in cell lines and in primary patient samples.
To reach the project aims different methods will be used: cell culture, vitality and apoptosis assay, western blot, flow cytometry and migration assay. Depending on the data obtained further methods like ELISA and gene expression profiling could also be used.

Organ repair by reconditioning aged, ischemic and steatotic rodent livers using normothermic, oxygenated long term machine perfusion

Supervisor: Prof. Dr. Utz Settmacher, Department for General, Visceral and Vascular Surgery

Contact: E-Mail, Tel: +49 3641 - 9 322 601

Project decription: Due to the demographic change also potential organ donors are becoming older and suffer from multimorbidity, resulting in a higher rate of marginal organ grafts offered for transplantation.. Reconditioning of marginal peri-operatively organs is one of the rare feasible strategies to rescue critical donor organ grafts. Machine perfusion was introduced recently to reduce the effects of prolonged ischemic storage of the organ. This project aims to reduce the effects of steatosis and high age by continuous long term machine perfusion.

Critical liver grafts due to age, steatosis or prolonged ischemia will be subjected to long term machine perfusion (24-72h) to assess damage and viability continuously. During this process organ grafts will be assessed by histology, Western blot, PCR and other methods to identify the key regulators processes prior to interfering with them.

The candidate should be willing to obtain the FELASA-licence and to learn all required assays including liver procurement and ex-vivo perfusion.

Tissue engineering of a porcine pulmonary conduit for interventional treatment of pulmonary hypertension

Supervisor: PD Dr. med. Jürgen Zanow, Department for General, Visceral and Vascular Surgery

Contact: E-Mail

Project decription: Aging is associated with an increased incidence of heart and lung disease. End stage disease can be complicated by pulmonary hypertension. Pulmonary hypertension leads to an increased stiffness and narrowing of the pulmonary artery due to elastin breakdown and collagen deposition resulting in the loss of the “windkessel” function. The ultimate treatment is lung transplantation which is only suitable for few patients. Interventional replacement of the heart valve together with a pulmonary conduit could be an alternative treatment option. One potential option is the use of decellularized pig conduits. However it remains unclear whether and to which extent the decellularization process affects the elastic properties of the arterial wall.

It is the aim of this project to develop a decellularization protocol and to characterize the resulting scaffold in respect to its composition and the morphological and mechanical properties.

The candidate should have an interest in biomechanical questions and techniques as well as histology and protein chemistry.

The potential of neural stem cells during aging: Neurogenesis, cognition and regeneration

Supervisor: Dr. Silke Keiner, RG Neural stem cells and adult neurogenesis, Department for Neurology

Contact: E-Mail, Tel: +49 3641 - 9 323 914

Project decription: In general, human longevity is associated with a decrease in cognitive performance. In addition to the deterioration of numerous functions, the ageing brain shows a certain degree of plasticity to compensate for these losses. One of these processes, called adult neurogenesis, involves the ability to generate new nerve cells in the dentate gyrus, part of the hippocampal formation, throughout one's life. The origin of adult neurogenesis is endogenous stem cells, which form mature neurons via complex neuronal developmental stages from proliferation to migration, differentiation and integration. These newly integrated neurons are functionally involved in learning and memory processes. Despite the continuous formation of new neurons, both the stem cell pool and adult neurogenesis decrease significantly during aging and are accompanied by a loss of cognitive functionality.
The aim of the research projects is to identify the processes leading to the decrease of the stem cell pool and neurogenesis during aging. Furthermore, new signalling pathways will be identified leading to restitution of lost stem cells and neurons in the dentate gyrus to improve cognitive performance in old age and during Alzheimer's disease.

Gut-brain Interaction in Age: Influence on Cognition

Supervisor: Dr. Christiane Frahm, RG Ageing and Plasticity, Department for Neurology

Contact: E-Mail

Project decription: It is well accepted that physical activity improves cognition even when started late in life, but the impact of the gut and the microbiota on brain plasticity especially in old organisms is still poorly understood.

Here we will expose mice to voluntary wheel running. We expect a cognitive improvement, a positive impact on the intestine and its microbiome and metabolites, an improved gut barrier function and a diminished inflammaging in old mice. This proposal represents a sub-project of the overall project and specifically includes: co-supervision of the animal experiments (wheel running), brain and colon sampling, RNA isolation and qPCR to investigate cerebral and colonic inflammatory processes. Brain tissue will be analyzed for transcript expression of pro-inflammatory cytokines, chemokines and markers for activated astrocytes and microglia. Colonic tissue will be analyzed for the same pro-inflammatory markers as the brain as well as by including genes that found up-regulated in inflammatory bowel disease. While the phenomena of inflammaging are well studied for the brain, there are hardly any findings for the intestine.
However, that's important to study because a changed inflammatory state of the colon in old age might impact gut brain communication and thus could create a vicious circle, which leads to neurodegenerative diseases.

Functional Analysis of De Novo Mutated Genes in Progression of Non-muscle Invasive Bladder Cancer (NMIBC)

Supervisor: Dr. Daniel Steinbach, Research Laboratory, Department for Urology

Contact: E-Mail, Tel: +49 3641 - 9 390 880

Project decription: Background: The incidence of NMIBC in Germany is about 13.700 per year. 10% - 15% of the cases progress to muscle invasive carcinoma (MIBC). Including primary invasive tumors, 15.800 people per year suffer from muscle-invasive bladder cancer (MIBC). Usually cystectomy is recommended because of worse prognosis of muscle-invasive disease. The mean age of first diagnosis of BCa is about 75 years. A major challenge at this age is the therapeutic approach and assurance of life quality after radical cystectomy. Due to the advanced age and the contraindications for a continent urinary diversion (poor compliance, self-catheterization, low life expectancy, renal insufficiency), an incontinent urinary diversion is often chosen, which needs a permanent nursing.
Currently, prognostic markers are not well known. Molecular targets, which could be helpful in therapy of progressive (high-risk) NMIBC to prevent invasion or as alternative therapy to cystectomy in MIBC, are not available.

Aim of the project and Methods: In comparative whole-exome sequencing of NMIBCs and corresponding MIBCs we identified tumor suppressor genes that showed de novo mutations during progression. A selection of these genes has to be investigated in functional assays regarding the influence on migration and invasion. The project includes the siRNA mediated knockdown or CRISPR/Cas mediated knockout and viral overexpression of genes in different bladder cancer cell lines, following by migration and invasion assays. In parallel, an organ model will be established to investigate the invasion of tumor cell lines into the muscularis of bladder. The aim of this project is to identify potential therapy targets for the progressive NMIBC.

The impact of age-related host factors on Staphylococcus aureus chronic infection development

Supervisors: PD Dr. Lorena Tuchscherr de Hauschopp, RG Tuchscherr, Institute for Medical Microbiology; Dr. Maria Ermolaeva, RG Stress Tolerance and Homeostasis, Leibniz Institute on Aging - Fritz Lipmann Institute (FLI)

Contact: E-Mail, Tel: +49 3641 - 9 393 628 (PD Dr. Lorena Tuchscherr de Hauschopp)
                E-Mail, Tel: +49 3641 - 656 805 (Dr. Maria Ermolaeva)

Project decription: Advanced age increases the susceptibility to infection. The ageing process is associated with chronic oxidative and inflammatory stress that leads to the damage of cell components, including organelles, proteins, lipids and DNA, and contributes to the age-induced decline of physiological functions. Such age-linked decline of host defence mechanisms most likely facilitates infection development and the progression to a chronic and difficult to treat infection courses. Mechanisms may include enhanced inflammation, pathogen-dependent tissue destruction, or accelerated cellular ageing. For instance, elderly patients often suffer from vertebral osteomyelitis, which is mainly caused by S. aureus and can induce severe complications However, the precise impact of age-related host responses to S. aureus is largely unknown. S. aureus is an opportunistic pathogen that colonizes the mucosal surface and causes many serious acute and chronic infections such as endocarditis, skin infection, sepsis and osteomyelitis. S. aureus can switch to a dormant phenotype, the so-called small colony variants (SCVs), which is associated with chronic and difficult to treat infections. SCVs are characterized by decreased metabolic activity, slower growth rate, lower virulence and less pigmentation than wild type phenotypes. In particular, SCVs have been adapted to intracellular survival and persistence, protecting them from immune surveillance and antibiotic treatment.

Recently, several models were developed by our group to study the pathobiology of S. aureus including our mouse model of staphylococcal haematogenous osteomyelitis which develops to chronicity and resembles most characteristics of the human disease. In our study, we will investigate whether the cellular oxidative and inflammatory stress associated with the ageing process enhance the bacterial fitness and the formation of SCVs contributing to the development of chronic infection. To investigate the impact of aging on the course of S. aureus infection, we will utilize cell culture models, C. elegans model and finally our murine haematogenous chronic osteomyelitis model. The understating of this process will open new therapeutic approaches to treat persisting infections in elderly hosts.

Analysis of risk factors for accelerated aging using BrainAGE

Supervisors: Prof. Dr. Christian Gaser, RG Structural Brain Mapping Group, Department for Neurology; Dr. Katja Franke, RG Structural Brain Mapping Group, Department for Neurology

Contact: E-Mail, Tel: +49 3641 - 9 325 778 (Prof. Dr. Christian Gaser)
                E-Mail, Tel: +49 3641 - 9 325 771 (Dr. Katja Franke)

Project decription: In the last decade, substantial efforts were put into the search for risk markers and modifiable (lifestyle) factors that promote the development of Alzheimer's Disease (AD) or on the other side could be protective against it. For late-onset AD, genetic variations in the Apolipoprotein E (APOE) gene were found to play an important role, with the APOEe4 allele being a major risk factor for AD (Chen et al., 2009). Regarding physical activity, most previous studies have supported the notion that physical activity can reduce risk of dementia, probably through improvement of cognitive function and overall health status (Chen et al., 2009). Further health and lifestyle markers have also been related to the risk of cognitive decline, accelerated brain atrophy, and dementia, including obesity, high cholesterol, nicotine and alcohol abuse, hypertension, diabetes, or elevated serum total homocysteine (tHcy) and lower levels of vitamin B12 (Chen et al., 2009; Solfrizzi et al., 2008).

Since accelerated brain atrophy was shown to precede cognitive impairment in MCI and AD, the quantification of miscellaneous risk factors (e.g. lifestyle factors, genetics, physical activity, and cognition/education) on individual brain aging will become even more important in order to predict the prospective cognitive decline and probable development of AD. Therefore, this project aims to find potential risk factors for accelerated brain aging as well as protecting factors that decelerate brain aging in a huge database (UK Biobank) with >10.000 brains.

The data will be analyzed using our novel BrainAGE approach that aggregates the multidimensional aging pattern across the whole brain into one single number. Using structural MRI data, the BrainAGE score quantifies acceleration or deceleration in individual brain aging and allows to predict the individual progression of mild cognitive impairment (MCI) to AD 3 years in advance with an accuracy of more than 80% (Gaser at al., 2013).

Functional role of astrocytes in learning-dependent brain plasticity – AstroPlast

Supervisors: Dr. Silvio Schmidt, Department for Neurology; Prof. Dr. Otto W. Witte, Department for Neurology

Contact: E-Mail, Tel: +49 3641 - 9 325 778 (Dr. Silvio Schmidt)
                E-Mail, Tel: +49 3641 - 9 325 771 (Prof. Dr. Otto W. Witte)

Project description: State of the art: High-resolution magnetic resonance imaging (MRI) allows the noninvasive detection of structural plasticity of the human brain over time. Learning is reflected as a specific spatial pattern of transient gray matter swellings. Aging-related decreased learning performance is associated with less pronounced swellings and the involvement of additional brain areas. The knowledge of the underlying cellular mechanisms would help to explain the aging-related decline in learning performance.

Preliminary work: Own results from analog studies on young experimental animals indicate that learning-related transient brain swelling is mainly mediated by reorganization and swelling of astrocytes. Project description: Based on this, astrocytes now will be be analyzed according to age in learning-related plastic brain areas on the morphological and transcriptional level.

Methods: Project-dependent, ultra-high field MRI measurements (9.4T), behavioral experiments, microscopy and cell-type specific gene expression analyzes with the help of various transgenic mouse lines and viral vector systems will be used.

Division-coupled loss of adult stem cells as mechanism of cognitive aging

Supervisor: Dr. Anja Urbach, RG Hippocampal Plasticity and Neurogenesis, Department for Neurology

Contact: E-Mail, Tel: +49 3641 - 9 325 901

Project description: The adult dentate gyrus is one of two brain regions that generate new neurons from multipotent stem cells throughout life. These cells integrate into the local circuits and contribute to hippocampal functions, such as declarative memory. We know that the potential to generate new neurons declines with increasing age, which is deemed to contribute to cognitive aging.

The underlying causes of this decline are still unclear, but likely include a successive loss of stem cell function. Two hypotheses attempt to explain this phenomenon: the stem cell “senescence” model proposes that the neural stem cells lose their mitotic potential over time; the stem cell “deforestation” model suggests that they differentiate into glia after a defined number of divisions. It is further known that adult neural stem cells divide asymmetrically, hence a significant expansion of the adult stem cell pool is extremely unlikely. Together, these data suggest that the lifelong neurogenic potential of the dentate gyrus is determined not only by mechanisms of stem cell aging but also by factors regulating the initial size of the stem cell pool during development.

The proposed project aims at unraveling the intrinsic mechanisms of stem cell aging and the associated decline in hippocampal function. Moreover, it attempts to elucidate the formation and developmental origin of the adult neural stem cell pool. To this end, we plan to implement single cell transcriptome analyses of the stem cell niche at critical timepoints during the life of mice.

Cytokine profiling and eQTL analyzes after extended hepatectomy

Supervisor: Dr. Hans-Michael Tautenhahn, Department for General, Visceral and Vascular Surgery

Contact: E-Mail, Tel: +49 3641 - 9 322 628

Projektbeschreibung: Aging is associated with a higher incidence of primary and secondary liver tumors requiring liver resection and extended resection. Liver resection is followed by liver regeneration to compensate the loss of liver mass. Liver regeneration is a complex reparative process requiring the orchestrated interplay of numerous signaling mechanism and signaling factors such as cytokines. Insufficient liver regeneration is associated with potentially life threatening hepatic dysfunction and failure.

The aim of this project is to characterize the serum cytokine profile in patients subjected to liver resection to identify factors supporting liver regeneration. Furthermore, liver tissue is used for expression quantitative trait loci (eQTLs). eQTL are genomic loci that explain all or a fraction of variation in expression levels of mRNAs. Correlation of serum cytokine profiles with the results of eQTL analysis should contribute to predict liver regeneration and to identify patients at risk for hepatic failure, both needed for later development of treatment strategies.

The candidate should be interested in translational research acquiring and using patient data and samples as well as in laboratory work and bioinformatics.

The role of CCL11 in microglia aging

Supervisor: Helen Morrison PhD, RG Nerve Regeneration, Leibniz Institute on Aging - Fritz Lipmann Institute (FLI)

Kontakt: E-Mail, Tel: +49 3641 - 656 139

Project description: The main purpose in this specific project is to investigate the role of the aging factor CCL11, also known as eotaxin-1, in mediation or induction of microglia aging. We (1) and others (2) have previously shown that CCL11 accumulates during aging in mice and men in the blood serum as well as in the cerebrospinal fluid (CSF). We have recently found, that CCL11 contributes to age-associated Schwann cell dysfunction leading to impaired peripheral nerve regeneration in aged mice (1). Another paper has previously shown that CCL11 in the aged mouse brain leads to impaired neurogenesis due to CCL11 induced impairment of neural stem cells which contributes to age-related central nervous system dysfunction in terms of impaired learning and memory (2). Furthermore, recently an effect of CCL11 on microglia was revealed: Cultured neurons treated with the conditioned media of CCL11 stimulated microglia induced neuronal reactive oxygen species (ROS) that ultimately lead to enhanced glutamate induced excitotoxic cell death of neurons (3). Our aim is to investigate a possible role of age-related accumulation of CCL11 in normal brain aging through induction of microglia aging and senescence. We plan to stimulate both BV-2 cells and primary microglia isolated from adult mice with CCL11 in vitro. Subsequently we want to dissect the cytokine expression profile and to investigate whether CCL11 regulates microglia polarization into either pro-or anti-inflammatory microglia. Furthermore, we will perform Western blotting to investigate the possible underlying signaling pathways mediating CCL11 induced microglia polarization as well as ROS-induced DNA damage as a possible mechanism in the induction of microglial senescence during aging. Phagocytosis experiments with fluorescently labeled myelin and apoptotic neurons as well as co-culture experiments with astrocytes will reveal alterations in CCL11 treated microglia in clearance ability and astrocyte activation. Lastly, we will use Western blotting to investigate the role of CCL11 in induction of 1. Microglia polarization, 2. DNA damage and 3. Subsequent altered astrocyte activation in vivo. Further immunofluorescence stainings of brains from young mice injected with either CCL11 (to accelerate brain aging) or control mice will reveal CCL11 mediated modulation of microglia morphology, phagocytic activity and activation in vivo.

1. R. Buttner et al., Inflammaging impairs peripheral nerve maintenance and regeneration. Aging Cell, e12833 (2018).
2. S. A. Villeda et al., The ageing systemic milieu negatively regulates neurogenesis and cognitive function. Nature 477, 90-94 (2011).
3. B. Parajuli, H. Horiuchi, T. Mizuno, H. Takeuchi, A. Suzumura, CCL11 enhances excitotoxic neuronal death by producing reactive oxygen species in microglia. Glia 63, 2274-2284 (2015).

Impact of aging on the induction of a tissue-destroying host response to chronic bacterial infection with pathogenic bacteria

Supervisors: Dr. Ulrike Schulze-Späte, Section of geriatric dentistry, Clinic for Conservation Dentistry (Odontology) and Periodontology, Centre for dental, oral and orthodontic medicine; Dr. Annika Döding, Section of geriatric dentistry, Clinic for Conservation Dentistry (Odontology) and Periodontology, Centre for dental, oral and orthodontic medicine

Contact: E-Mail, Tel: +49 3641 - 9 34 543 (Dr. Ulrike Schulze-Späte)
                E-Mail, Tel: +49 3641 - 9 396 722 (Dr. Annika Döding)

Project description: Chronic bacterial infections induce cytokine and pro-inflammatory signaling pathways that can lead to bone loss by promoting an imbalance in the activity of osteoblast and osteoclasts and, therefore, foster establishment of local (periodontitis) bone disease. What remains poorly understood is the influence of aging on the induction of a tissue destructive host response to chronic bacterial infection with pathogenic bacteria, which is the main focus of the project.

The experimental design includes cell culture work with primary cells and cell lines, molecular biological techniques, analysis of histological sections taken from humans and mouse studies.