Wiebke Lückstädt

Bio: Wiebke Lückstädt is an academic researcher from University of Kiel. The author has contributed to research in topics: Metalloproteinase & Phosphorylation. The author has an hindex of 1, co-authored 4 publications receiving 8 citations.

Joint Reconstituted Signaling of the IL-6 Receptor via Extracellular Vesicles

Abstract: Interleukin-6 (IL-6) signaling is a crucial regulatory event important for many biological functions, such as inflammation and tissue regeneration. Accordingly, several pathological conditions are associated with dysregulated IL-6 activity, making it an attractive therapeutic target. For instance, blockade of IL-6 or its α-receptor (IL-6R) by monoclonal antibodies has been successfully used to treat rheumatoid arthritis. However, based on different signaling modes, IL-6 function varies between pro- and anti-inflammatory activity, which is critical for therapeutic intervention. So far, three modes of IL-6 signaling have been described, the classic anti-inflammatory signaling, as well as pro-inflammatory trans-signaling, and trans-presentation. The IL-6/IL-6R complex requires an additional β-receptor (gp130), which is expressed on almost all cells of the human body, to induce STAT3 (signal transducer and activator of signal transcription 3) phosphorylation and subsequent transcriptional regulation. In contrast, the IL-6R is expressed on a limited number of cells, including hepatocytes and immune cells. However, the proteolytic release of the IL-6R enables trans-signaling on cells expressing gp130 only. Here, we demonstrate a fourth possibility of IL-6 signaling that we termed joint reconstituted signaling (JRS). We show that IL-6R on extracellular vesicles (EVs) can also be transported to and fused with other cells that lack the IL-6R on their surface. Importantly, JRS via EVs induces delayed STAT3 phosphorylation compared to the well-established trans-signaling mode. EVs isolated from human serum were already shown to carry the IL-6R, and thus this new signaling mode should be considered with regard to signal intervention.

Cell Surface Processing of CD109 by Meprin β Leads to the Release of Soluble Fragments and Reduced Expression on Extracellular Vesicles

Abstract: Cluster of differentiation 109 (CD109) is a glycosylphosphatidylinositol (GPI)-anchored protein expressed on primitive hematopoietic stem cells, activated platelets, CD4+ and CD8+ T cells, and keratinocytes. In recent years, CD109 was also associated with different tumor entities and identified as a possible future diagnostic marker linked to reduced patient survival. Also, different cell signaling pathways were proposed as targets for CD109 interference including the TGFβ, JAK-STAT3, YAP/TAZ, and EGFR/AKT/mTOR pathways. Here, we identify the metalloproteinase meprin β to cleave CD109 at the cell surface and thereby induce the release of cleavage fragments of different size. Major cleavage was identified within the bait region of CD109 residing in the middle of the protein. To identify the structural localization of the bait region, homology modeling and single-particle analysis were applied, resulting in a molecular model of membrane-associated CD109, which allows for the localization of the newly identified cleavage sites for meprin β and the previously published cleavage sites for the metalloproteinase bone morphogenetic protein-1 (BMP-1). Full-length CD109 localized on extracellular vesicles (EVs) was also identified as a release mechanism, and we can show that proteolytic cleavage of CD109 at the cell surface reduces the amount of CD109 sorted to EVs. In summary, we identified meprin β as the first membrane-bound protease to cleave CD109 within the bait region, provide a first structural model for CD109, and show that cell surface proteolysis correlates negatively with CD109 released on EVs.

A blood marker for Parkinson’s Disease: Neuronal exosome-derived α-synuclein

Abstract: To date, no reliable clinically applicable biomarker has been established for Parkinson’s disease (PD). Our results indicate that a long hoped blood test for Parkinson’s disease may be realized. We here assess the potential of pathological α-synuclein originating from neuron-derived exosomes from blood plasma as a possible biomarker. Following the isolation of neuron-derived exosomes from plasma of PD patients and non-PD individuals immunoblot analyses were performed to detect exosomal α-synuclein. Under native conditions significantly increased signals of disease-associated α-synuclein forms in neuron-derived exosomes were measured in all individuals with PD and clearly distinguished PD samples from controls. By performing a protein misfolding cyclic amplification assay these aggregates could be amplified and seeding could be demonstrated. Moreover, the aggregates exhibited β-sheet-rich structures and showed a fibrillary appearance. Our study demonstrates that the detection of pathological α-synuclein conformers from neuron-derived exosomes from plasma samples has the potential of a promising blood-biomarker of PD.

Validation of the MDS Clinical Diagnostic Criteria for Parkinson’s Disease (S3.001)

Abstract: Objective: To validate the International Parkinson Disease and Movement Disorders society (MDS) diagnostic criteria against a gold-standard expert clinical diagnosis and to compare concordance/accuracy of the MDS criteria to 1988 United Kingdom brain bank criteria. Background: In 2015, the MDS published the new clinical diagnostic criteria for Parkinson’s disease (PD). These criteria aimed to codify/reproduce the expert clinical diagnostic process, to help standardize diagnosis in research and clinical settings. Their accuracy compared to expert clinical diagnosis has not been tested. Design/Methods: From 8 centers, we recruited 626 patients with parkinsonism (434 with PD and 192 with other causes, diagnosed by an expert treating physician). A second, less experienced neurologist evaluated the presence/absence of each individual item from the diagnostic criteria. The overall accuracy/concordance rate, sensitivity, and specificity of diagnostic criteria were calculated. Results: Of 434 patients diagnosed with PD, 94.5% met MDS criteria for probable PD (i.e. a 5.5% false-negative rate). Of 192 non-PD patients, 88.5% were identified as non-PD by the criteria (i.e. a 11.5% false-positive rate). The overall accuracy for probable PD was 92.6%. For the clinically-established PD category, 59.3% of PD patients and only 1.6% of non-PD patients met MDS criteria. Compared to MDS probable PD criteria, the UK brain bank criteria had significantly lower sensitivity (89.2%, p=0.008), specificity (79.2%, p=0.018), and overall accuracy (86.4%, p Conclusions: The MDS criteria demonstrated high sensitivity and specificity compared to gold-standard expert diagnosis. To meet the unmet gap of specific diagnostic criteria for early PD, we suggest additional ‘Clinically-Established Early PD’ criteria to be used for clinical trials of early PD. Study Supported by: Michael J. Fox Foundation Disclosure: Dr. Postuma has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Biotie, Roche/Prothena, Teva Neurosciences, Jazz Pharmaceuticals, Novartis Canada, Theranexus, GE HealthCare, . Dr. Poewe has nothing to disclose. Dr. Litvan has received personal compensation for serving onthe scientific steering committee of the Biotie/Parkinson Study Group clinical trial Dr. Lewis has nothing to disclose. Dr. Lang has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Abbvie, Acorda, Avanir Pharmaceuticals, Biogen, Bristol Myers Squibb, Sun Pharma, Cipla, Intekrin, Merck, Medichem, Medtronic, Teva, UCB, and Sunovion, . Dr. Halliday has nothing to disclose. Dr. Goetz has nothing to disclose. Dr. Chan has nothing to disclose. Dr. Slow has nothing to disclose. Dr. Seppi has nothing to disclose. Dr. Schaeffer has nothing to disclose. Dr. Berg has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with UCB Pharma GmbH, Lundbeck, Prexton Therapeutics, GE-Healthcare. Dr. Rios Romenets has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with NIA, Genentech/Roche. Dr. Rios Romenets has received research support from NIA, Genentech/Roche. Dr. Mi has nothing to disclose. Dr. Maetzler has nothing to disclose. Dr. Li has nothing to disclose. Dr. Heim has nothing to disclose. Dr. Bledsoe has nothing to disclose.

Detection of neuron-derived pathological α-synuclein in blood.

Abstract: To date, no reliable clinically applicable biomarker has been established for Parkinson's disease. Our results indicate that a long anticipated blood test for Parkinson's disease may be realized. Following the isolation of neuron-derived extracellular vesicles of Parkinson's disease patients and non-Parkinson's disease individuals, immunoblot analyses were performed to detect extracellular vesicle-derived α-synuclein. Pathological α-synuclein forms derived from neuronal extracellular vesicles could be detected under native conditions and were significantly increased in all individuals with Parkinson's disease and clearly distinguished disease from the non-disease state. By performing an α-synuclein seeding assay these soluble conformers could be amplified and seeding of pathological protein folding was demonstrated. Amplified α-synuclein conformers exhibited β-sheet-rich structures and a fibrillary appearance. Our study demonstrates that the detection of pathological α-synuclein conformers from neuron-derived extracellular vesicles from blood plasma samples has the potential to evolve into a blood-biomarker of Parkinson's disease that is still lacking so far. Moreover, the distribution of seeding-competent α-synuclein within blood exosomes sheds a new light of pathological disease mechanisms in neurodegenerative disorders.

OUP accepted manuscript

Abstract: To date, no reliable clinically applicable biomarker has been established for Parkinson's disease. Our results indicate that a long anticipated blood test for Parkinson's disease may be realized. Following the isolation of neuron-derived extracellular vesicles of Parkinson's disease patients and non-Parkinson's disease individuals, immunoblot analyses were performed to detect extracellular vesicle-derived α-synuclein. Pathological α-synuclein forms derived from neuronal extracellular vesicles could be detected under native conditions and were significantly increased in all individuals with Parkinson's disease and clearly distinguished disease from the non-disease state. By performing an α-synuclein seeding assay these soluble conformers could be amplified and seeding of pathological protein folding was demonstrated. Amplified α-synuclein conformers exhibited β-sheet-rich structures and a fibrillary appearance. Our study demonstrates that the detection of pathological α-synuclein conformers from neuron-derived extracellular vesicles from blood plasma samples has the potential to evolve into a blood-biomarker of Parkinson's disease that is still lacking so far. Moreover, the distribution of seeding-competent α-synuclein within blood exosomes sheds a new light of pathological disease mechanisms in neurodegenerative disorders.

Robustness and Information Transfer within IL-6-induced JAK/STAT Signalling

Abstract: Cellular communication via intracellular signalling pathways is crucial. Expression and activation of signalling proteins is heterogenous between isogenic cells of the same cell-type. However, mechanisms evolved to enable sufficient communication and to ensure cellular functions. We use information theory to clarify mechanisms facilitating IL-6-induced JAK/STAT signalling despite cell-to-cell variability. We show that different mechanisms enabling robustness against variability complement each other. Early STAT3 activation is robust as long as cytokine concentrations are low. Robustness at high cytokine concentrations is ensured by high STAT3 expression or serine phosphorylation. Later the feedback-inhibitor SOCS3 increases robustness. Channel Capacity of JAK/STAT signalling is limited by cell-to-cell variability in STAT3 expression and is affected by the same mechanisms governing robustness. Increasing STAT3 amount increases Channel Capacity and robustness, whereas increasing STAT3 tyrosine phosphorylation reduces robustness but increases Channel Capacity. In summary, we elucidate mechanisms preventing dysregulated signalling by enabling reliable JAK/STAT signalling despite cell-to-cell heterogeneity.