Publications by authors named "Martin Lenter"

26 Publications

  • Page 1 of 1

Identification of a myotropic AAV by massively parallel in vivo evaluation of barcoded capsid variants.

Nat Commun 2020 10 28;11(1):5432. Epub 2020 Oct 28.

Heidelberg University Hospital, Dept. of Infectious Diseases/Virology, Cluster of Excellence CellNetworks, 69120, Heidelberg, Germany.

Adeno-associated virus (AAV) forms the basis for several commercial gene therapy products and for countless gene transfer vectors derived from natural or synthetic viral isolates that are under intense preclinical evaluation. Here, we report a versatile pipeline that enables the direct side-by-side comparison of pre-selected AAV capsids in high-throughput and in the same animal, by combining DNA/RNA barcoding with multiplexed next-generation sequencing. For validation, we create three independent libraries comprising 183 different AAV variants including widely used benchmarks and screened them in all major tissues in adult mice. Thereby, we discover a peptide-displaying AAV9 mutant called AAVMYO that exhibits superior efficiency and specificity in the musculature including skeletal muscle, heart and diaphragm following peripheral delivery, and that holds great potential for muscle gene therapy. Our comprehensive methodology is compatible with any capsids, targets and species, and will thus facilitate and accelerate the stratification of optimal AAV vectors for human gene therapy.
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http://dx.doi.org/10.1038/s41467-020-19230-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7595228PMC
October 2020

The RESOLUTE consortium: unlocking SLC transporters for drug discovery.

Authors:
Giulio Superti-Furga Daniel Lackner Tabea Wiedmer Alvaro Ingles-Prieto Barbara Barbosa Enrico Girardi Ulrich Goldmann Bettina Gürtl Kristaps Klavins Christoph Klimek Sabrina Lindinger Eva Liñeiro-Retes André C Müller Svenja Onstein Gregor Redinger Daniela Reil Vitaly Sedlyarov Gernot Wolf Matthew Crawford Robert Everley David Hepworth Shenping Liu Stephen Noell Mary Piotrowski Robert Stanton Hui Zhang Salvatore Corallino Andrea Faedo Maria Insidioso Giovanna Maresca Loredana Redaelli Francesca Sassone Lia Scarabottolo Michela Stucchi Paola Tarroni Sara Tremolada Helena Batoulis Andreas Becker Eckhard Bender Yung-Ning Chang Alexander Ehrmann Anke Müller-Fahrnow Vera Pütter Diana Zindel Bradford Hamilton Martin Lenter Diana Santacruz Coralie Viollet Charles Whitehurst Kai Johnsson Philipp Leippe Birgit Baumgarten Lena Chang Yvonne Ibig Martin Pfeifer Jürgen Reinhardt Julian Schönbett Paul Selzer Klaus Seuwen Charles Bettembourg Bruno Biton Jörg Czech Hélène de Foucauld Michel Didier Thomas Licher Vincent Mikol Antje Pommereau Frédéric Puech Veeranagouda Yaligara Aled Edwards Brandon J Bongers Laura H Heitman Ad P IJzerman Huub J Sijben Gerard J P van Westen Justine Grixti Douglas B Kell Farah Mughal Neil Swainston Marina Wright-Muelas Tina Bohstedt Nicola Burgess-Brown Liz Carpenter Katharina Dürr Jesper Hansen Andreea Scacioc Giulia Banci Claire Colas Daniela Digles Gerhard Ecker Barbara Füzi Viktoria Gamsjäger Melanie Grandits Riccardo Martini Florentina Troger Patrick Altermatt Cédric Doucerain Franz Dürrenberger Vania Manolova Anna-Lena Steck Hanna Sundström Maria Wilhelm Claire M Steppan

Nat Rev Drug Discov 2020 07;19(7):429-430

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http://dx.doi.org/10.1038/d41573-020-00056-6DOI Listing
July 2020

Quantitative Profiling of the Human Substantia Nigra Proteome from Laser-capture Microdissected FFPE Tissue.

Mol Cell Proteomics 2020 05 4;19(5):839-851. Epub 2020 Mar 4.

Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, United Kingdom. Electronic address:

Laser-capture microdissection (LCM) allows the visualization and isolation of morphologically distinct subpopulations of cells from heterogeneous tissue specimens. In combination with formalin-fixed and paraffin-embedded (FFPE) tissue it provides a powerful tool for retrospective and clinically relevant studies of tissue proteins in a healthy and diseased context. We first optimized the protocol for efficient LCM analysis of FFPE tissue specimens. The use of SDS containing extraction buffer in combination with the single-pot solid-phase-enhanced sample preparation (SP3) digest method gave the best results regarding protein yield and protein/peptide identifications. Microdissected FFPE human substantia nigra tissue samples (∼3,000 cells) were then analyzed, using tandem mass tag (TMT) labeling and LC-MS/MS, resulting in the quantification of >5,600 protein groups. Nigral proteins were classified and analyzed by abundance, showing an enrichment of extracellular exosome and neuron-specific gene ontology (GO) terms among the higher abundance proteins. Comparison of microdissected samples with intact tissue sections, using a label-free shotgun approach, revealed an enrichment of neuronal cell type markers, such as tyrosine hydroxylase and alpha-synuclein, as well as proteins annotated with neuron-specific GO terms. Overall, this study provides a detailed protocol for laser-capture proteomics using FFPE tissue and demonstrates the efficiency of LCM analysis of distinct cell subpopulations for proteomic analysis using low sample amounts.
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http://dx.doi.org/10.1074/mcp.RA119.001889DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7196589PMC
May 2020

Structural and Functional Characterization of Ubiquitin Variant Inhibitors of USP15.

Structure 2019 04 31;27(4):590-605.e5. Epub 2019 Jan 31.

The Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada. Electronic address:

The multi-domain deubiquitinase USP15 regulates diverse eukaryotic processes and has been implicated in numerous diseases. We developed ubiquitin variants (UbVs) that targeted either the catalytic domain or each of three adaptor domains in USP15, including the N-terminal DUSP domain. We also designed a linear dimer (diUbV), which targeted the DUSP and catalytic domains, and exhibited enhanced specificity and more potent inhibition of catalytic activity than either UbV alone. In cells, the UbVs inhibited the deubiquitination of two USP15 substrates, SMURF2 and TRIM25, and the diUbV inhibited the effects of USP15 on the transforming growth factor β pathway. Structural analyses revealed that three distinct UbVs bound to the catalytic domain and locked the active site in a closed, inactive conformation, and one UbV formed an unusual strand-swapped dimer and bound two DUSP domains simultaneously. These inhibitors will enable the study of USP15 function in oncology, neurology, immunology, and inflammation.
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http://dx.doi.org/10.1016/j.str.2019.01.002DOI Listing
April 2019

Targeting blood-brain-barrier transcytosis - perspectives for drug delivery.

Neuropharmacology 2017 Jul 22;120:4-7. Epub 2016 Aug 22.

Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.

Efficient transcytosis across the blood-brain-barrier (BBB) is an important strategy for accessing drug targets within the central nervous system (CNS). Despite extensive research the number of studies reporting successful delivery of macromolecules or macromolecular complexes to the CNS has remained very low. In order to expand current research it is important to know which receptors are selective and abundant on the BBB so that novel CNS-targeting antibodies or other ligands could be developed, targeting those receptors for transcytosis. To do that, we have set up a proteomics- and transcriptomics-based workflow within the COMPACT project (Collaboration on the Optimization of Macromolecular Pharmaceutical Access to Cellular Targets) of the Innovative Medicines Initiative (IMI) of the EU. Here we summarise our overall strategy in endothelial transcytosis research, describe in detail the related challenges, and discuss future perspectives of these studies. This article is part of the Special Issue entitled "Beyond small molecules for neurological disorders".
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http://dx.doi.org/10.1016/j.neuropharm.2016.08.025DOI Listing
July 2017

Design, synthesis and evaluation of MCH receptor 1 antagonists--Part I: Optimization of HTS hits towards an in vivo efficacious tool compound BI 414.

Bioorg Med Chem Lett 2015 Aug 6;25(16):3264-9. Epub 2015 Jun 6.

Boehringer Ingelheim Pharma GmbH & Co. KG, Department of Medicinal Chemistry, Birkendorfer Str. 65, 88397 Biberach an der Riss, Germany.

Despite recent approvals of anti-obesity drugs there is still a high therapeutic need for alternative options with higher efficacy in humans. As part of our MCH-R1 antagonist program for the treatment of obesity, a series of biphenylacetamide HTS hits was evaluated. Several issues of the initial lead structures had to be resolved, such as potency, selectivity over related GPCRs and P-gp efflux limiting brain exposure in this series. We could demonstrate that all parameters can be significantly improved by structural modifications resulting in BI 414 as a potent and orally available MCH-R1 antagonist tool compound with acceptable in vivo efficacy in an animal model of obesity.
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http://dx.doi.org/10.1016/j.bmcl.2015.05.077DOI Listing
August 2015

Design, synthesis and evaluation of MCH receptor 1 antagonists--Part III: Discovery of pre-clinical development candidate BI 186908.

Bioorg Med Chem Lett 2015 Aug 29;25(16):3275-80. Epub 2015 May 29.

Boehringer Ingelheim Pharma GmbH & Co. KG, Department of Medicinal Chemistry, Research Germany, Birkendorfer Str. 65, 88397 Biberach an der Riss, Germany.

Although overweight and obesity are highly prevalent conditions, options to treat them are still very limited. As part of our search for safe and effective MCH-R1 antagonists for the treatment of obesity, two series of pyridones and pyridazinones were evaluated. Optimization was aimed at improving DMPK properties by increasing metabolic stability and improving the safety profile by reducing inhibition of the hERG channel and reducing the potential to induce phospholipidosis. Steric shielding of a labile keto moiety with an ortho-methyl group and fine-tuning of the polarity in several parts of the molecule resulted in BI 186908 (11 g), a potent and selective MCH-R1 antagonist with favorable DMPK and CMC properties. Chronic administration of BI 186908 resulted in significant body weight reduction comparable to sibutramine in a 4 week diet-induced obesity model in rats. Based on its favorable safety profile, BI 186908 was advanced to pre-clinical development.
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http://dx.doi.org/10.1016/j.bmcl.2015.05.065DOI Listing
August 2015

Design, synthesis and evaluation of MCH receptor 1 antagonists--Part II: Optimization of pyridazines toward reduced phospholipidosis and hERG inhibition.

Bioorg Med Chem Lett 2015 Aug 30;25(16):3270-4. Epub 2015 May 30.

Boehringer Ingelheim Pharma GmbH & Co. KG, Department of Medicinal Chemistry, Research Germany, Birkendorfer Str. 65, 88397 Biberach an der Riss, Germany.

Despite recent success there remains a high therapeutic need for the development of drugs targeting diseases associated with the metabolic syndrome. As part of our search for safe and effective MCH-R1 antagonists for the treatment of obesity, a series of 3,6-disubstituted pyridazines was evaluated. During optimization several issues of the initial lead structures had to be resolved, such as selectivity over related GPCRs, inhibition of the hERG channel as well as the potential to induce phospholipidosis. Utilizing property-based design, we could demonstrate that all parameters can significantly be improved by consequently increasing the polarity of the compounds. By this strategy, we succeeded in identifying potent and orally available MCH-R1 antagonists with good selectivity over M1 and 5-HT2A and an improved safety profile with respect to hERG inhibition and phospholipidosis.
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http://dx.doi.org/10.1016/j.bmcl.2015.05.074DOI Listing
August 2015

Crystal structure of glucokinase regulatory protein.

Biochemistry 2013 May 9;52(20):3523-31. Epub 2013 May 9.

Departments of Lead Identification and Optimization Support, ‡CardioMetabolic Diseases Research, §CNS Diseases Research, ∥Drug Discovery Support, ⊥BP Process Science, and @Medicinal Chemistry, Boehringer Ingelheim Pharma GmbH & Company KG , Biberach an der Riss, Germany.

Glucokinase (GK) plays a major role in the regulation of blood glucose homeostasis in both the liver and the pancreas. In the liver, GK is controlled by the GK regulatory protein (GKRP). GKRP in turn is activated by fructose 6-phosphate (F6P) and inactivated by fructose 1-phosphate (F1P). Disrupting the GK-GKRP complex increases the activity of GK in the cytosol and is considered an attractive concept for the regulation of blood glucose. We have determined the crystal structure of GKRP in its inactive F1P-bound form. The binding site for F1P is located deeply buried at a domain interface, and H-D exchange experiments confirmed that F1P and F6P compete for this site. The structure of the inactive GKRP-F1P complex provides a starting point for understanding the mechanism of fructose phosphate-dependent GK regulation at an atomic level.
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http://dx.doi.org/10.1021/bi4000782DOI Listing
May 2013

Differential sialylation of serpin A1 in the early diagnosis of Parkinson's disease dementia.

PLoS One 2012 8;7(11):e48783. Epub 2012 Nov 8.

Department of Neurology, University of Ulm, Ulm, Germany.

The prevalence of Parkinson's disease (PD) increases with age. Up to 50% of PD show cognitive decline in terms of a mild cognitive impairment already in early stages that predict the development of dementia, which can occur in up to 80% of PD patients over the long term, called Parkinson's disease dementia (PDD). So far, diagnosis of PD/PDD is made according to clinical and neuropsychological examinations while laboratory data is only used for exclusion of other diseases. The aim of this study was the identification of possible biomarkers in cerebrospinal fluid (CSF) of PD, PDD and controls (CON) which predict the development of dementia in PD. For this, a proteomic approach optimized for CSF was performed using 18 clinically well characterized patients in a first step with subsequent validation using 84 patients. Here, we detected differentially sialylated isoforms of Serpin A1 as marker for differentiation of PD versus PDD in CSF. Performing 2D-immunoblots, all PDD patients could be identified correctly (sensitivity 100%). Ten out of 24 PD patients showed Serpin A1 isoforms in a similar pattern like PDD, indicating a specificity of 58% for the test-procedure. In control samples, no additional isoform was detected. On the basis of these results, we conclude that differentially sialylated products of Serpin A1 are an interesting biomarker to indicate the development of a dementia during the course of PD.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0048783PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3493604PMC
May 2013

iTRAQ and multiple reaction monitoring as proteomic tools for biomarker search in cerebrospinal fluid of patients with Parkinson's disease dementia.

Exp Neurol 2012 Apr 1;234(2):499-505. Epub 2012 Feb 1.

Department of Neurology, University of Ulm, Germany.

About 30% of patients with Parkinson's disease (PD) develop Parkinson's disease dementia (PDD) in the course of the disease. Until now, diagnosis is based on clinical and neuropsychological examinations, since so far there is no laboratory marker. In this study we aimed to find a neurochemical marker which would allow a risk assessment for the development of a dementia in PD patients. For this purpose, we adopted a gel-free proteomic approach (iTRAQ-method) to identify biomarker-candidates in the cerebrospinal fluid (CSF) of patients with PD, PDD and non-demented controls (NDC). Validation of these candidates was then carried out by multiple-reaction-monitoring (MRM) optimised for CSF. Using the iTRAQ-approach, we were able to identify 16 differentially regulated proteins. Fourteen out of these 16 proteins could then be followed-up simultaneously in our optimised MRM-measurement protocol. However only Tyrosine-kinase-non-receptor-type 13 and Netrin-G1 differed significantly between PDD and NDC cohorts. In addition, a significant difference was found for Golgin-160 and Apolipoprotein B-100 between PD and NDC. Apart from possible pathophysiological considerations, we propose that Tyrosine-kinase non-receptor-type 13 and Netrin G1 are biomarker candidates for the development of a Parkinson's disease dementia. Furthermore we suggest that iTRAQ and MRM are valuable tools for the discovery of biomarker in cerebrospinal fluid. However further validation studies need to be done with larger patient cohorts and other proteins need to be checked as well.
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http://dx.doi.org/10.1016/j.expneurol.2012.01.024DOI Listing
April 2012

Next-generation insights into regulatory T cells: expression profiling and FoxP3 occupancy in Human.

Nucleic Acids Res 2011 Oct 4;39(18):7946-60. Epub 2011 Jul 4.

Department of Pulmonary Research, Group Genomics, Boehringer Ingelheim Pharma GmbH & Co KG, Birkendorferstraße 67, 88397 Biberach an der Riß, Germany.

Regulatory T-cells (Treg) play an essential role in the negative regulation of immune answers by developing an attenuated cytokine response that allows suppressing proliferation and effector function of T-cells (CD4(+) Th). The transcription factor FoxP3 is responsible for the regulation of many genes involved in the Treg gene signature. Its ablation leads to severe immune deficiencies in human and mice. Recent developments in sequencing technologies have revolutionized the possibilities to gain insights into transcription factor binding by ChiP-seq and into transcriptome analysis by mRNA-seq. We combine FoxP3 ChiP-seq and mRNA-seq in order to understand the transcriptional differences between primary human CD4(+) T helper and regulatory T-cells, as well as to study the role of FoxP3 in generating those differences. We show, that mRNA-seq allows analyzing the transcriptomal landscape of T-cells including the expression of specific splice variants at much greater depth than previous approaches, whereas 50% of transcriptional regulation events have not been described before by using diverse array technologies. We discovered splicing patterns like the expression of a kinase-dead isoform of IRAK1 upon T-cell activation. The immunoproteasome is up-regulated in both Treg and CD4(+) Th cells upon activation, whereas the 'standard' proteasome is up-regulated in Tregs only upon activation.
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http://dx.doi.org/10.1093/nar/gkr444DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3185410PMC
October 2011

Large scale preparation of human MHC class II+ integrin beta(1)+ Tregs.

J Immunol Methods 2010 Aug 25;360(1-2):96-102. Epub 2010 Jun 25.

Gen-Probe Diaclone SAS, 1 Boulevard A. Fleming, 25020 Besançon, France.

The human CD4+CD25+FoxP3+ regulatory T cell population (Tregs) contains both MHC class II+ and MHC class II(-) cells. MHC class II+ Tregs belong to the integrin alpha(4)beta(1)+ subpopulation and exclusively execute contact-dependent suppressive activity. Here we present a method optimized for isolation of these MHC class II expressing Tregs from large leukaphereses products using magnetic microbeads that achieves a reproducible purity of more than 90% and enables the use of this small-sized Treg population in pre-clinical application and basic research.
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http://dx.doi.org/10.1016/j.jim.2010.06.014DOI Listing
August 2010

EGFL6 is increasingly expressed in human obesity and promotes proliferation of adipose tissue-derived stromal vascular cells.

Mol Cell Biochem 2010 Oct 25;343(1-2):257-69. Epub 2010 Jun 25.

Department of CardioMetabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co KG, Biberach, Germany.

With increasing rates of obesity driving the incidence of type 2 diabetes and cardiovascular diseases to epidemic levels, understanding of the biology of adipose tissue expansion is a focus of current research. Identification and characterization of secreted proteins of the adipose tissue could provide further insights into the function of adipose tissue and might help to therapeutically influence the development of obesity and associated metabolic disorders. In the present study, we identified human epidermal growth factor-like domain multiple-6 (EGFL6) as an adipose tissue-secreted protein. EGFL6 expression in human subcutaneous adipose tissue significantly increased with obesity and decreased after weight loss. Further, expression and secretion of EGFL6 increased with in vitro differentiation of human preadipocytes, suggesting that mature adipocytes are the main source of EGFL6. Containing epidermal growth factor (EGF)-like repeats, an Arg-Gly-Asp (RGD) integrin binding motif and a mephrin, A5 protein and receptor protein-tyrosine phosphatase mu (MAM) domain, EGFL6 was suggested to be an extra-cellular matrix protein. Recombinant human EGFL6 protein mediated cell adhesion of human adipose tissue-derived stromal vascular cells (AD-SVC) in an RGD-dependent manner. FACS analyses revealed specific binding of the protein to the cell surface of AD-SVC with the binding being predominantly mediated by the EGF-like repeats. Recombinant EGFL6 enhanced proliferation of human AD-SVC as measured by MTS assay and [(14)C]-thymidine incorporation. These results indicate that human EGFL6 is a paracrine/autocrine growth factor of adipose tissue up-regulated in obesity and potentially involved in the process of adipose tissue expansion and the development of obesity.
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http://dx.doi.org/10.1007/s11010-010-0521-7DOI Listing
October 2010

Generation of monoclonal antibodies against human regulatory T cells.

J Immunol Methods 2010 Feb 22;353(1-2):62-70. Epub 2010 Jan 22.

Department of Dermatology of University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstrasse1, 55101 Mainz, Germany.

Natural CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) control the activation of the immune system and therefore have become a major area of research in immunology. The generation of monoclonal antibodies against human Tregs offers the possibility to discover novel Treg-specific or Treg-associated surface markers and to identify targets for a therapeutic modulation of Tregs. Here we present a methodology optimized to efficiently induce and select mAb against human Tregs by repeated immunization of mice with Tregs from a single donor and a differential two-step flow cytometry-based hybridoma screening procedure.
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http://dx.doi.org/10.1016/j.jim.2010.01.002DOI Listing
February 2010

Ubiquitin as potential cerebrospinal fluid marker of Creutzfeldt-Jakob disease.

Proteomics 2010 Jan;10(1):81-9

Department of Neurology, University of Ulm, Germany.

Until today, a definite diagnosis of Creutzfeldt-Jakob disease (CJD) can only be made neuropathologically. At lifetime the early and differential diagnosis is often a problem. With SELDI we analyzed cerebrospinal fluid (CSF) from 32 CJD patients, 32 patients having other dementive diseases and 31 non-demented control subjects for diagnosis-dependent protein pattern differences. In a screening set of patients, peaks that discriminate best between groups were identified. These peaks were subsequently analyzed using an independent validation set of patients. Diagnostic accuracies were compared with established markers like tau protein and 14-3-3-protein. Potential marker proteins were purified and identified by LC-MS/MS. In the validation set only one peak of 8.6 kDa out of ten in the screening set could be confirmed. This protein was identified to be ubiquitin and increased levels in CSF (but not in serum) of CJD patients were confirmed by Western blot. Ubiquitin allows the correct diagnoses of that CJD cases missed by tau protein or 14-3-3-protein. We conclude that ubiquitin is a promising additional CSF biomarker for diagnosis of CJD, especially in differential diagnostically difficult cases. The selective increase of ubiquitin in CSF of CJD patients might point to an involvement of ubiquitin in pathophysiological process.
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http://dx.doi.org/10.1002/pmic.200900246DOI Listing
January 2010

miR-155 inhibition sensitizes CD4+ Th cells for TREG mediated suppression.

PLoS One 2009 Sep 24;4(9):e7158. Epub 2009 Sep 24.

Boehringer Ingelheim Pharma GmbH & Co. KG, Respiratory Diseases Research, Genomics Group, Biberach an der Riss, Germany.

Background: In humans and mice naturally occurring CD4(+)CD25(+) regulatory T cells (nTregs) are a thymus-derived subset of T cells, crucial for the maintenance of peripheral tolerance by controlling not only potentially autoreactive T cells but virtually all cells of the adaptive and innate immune system. Recent work using Dicer-deficient mice irrevocably demonstrated the importance of miRNAs for nTreg cell-mediated tolerance.

Principal Findings: DNA-Microarray analyses of human as well as murine conventional CD4(+) Th cells and nTregs revealed a strong up-regulation of mature miR-155 (microRNA-155) upon activation in both populations. Studying miR-155 expression in FoxP3-deficient scurfy mice and performing FoxP3 ChIP-Seq experiments using activated human T lymphocytes, we show that the expression and maturation of miR-155 seem to be not necessarily regulated by FoxP3. In order to address the functional relevance of elevated miR-155 levels, we transfected miR-155 inhibitors or mature miR-155 RNAs into freshly-isolated human and mouse primary CD4(+) Th cells and nTregs and investigated the resulting phenotype in nTreg suppression assays. Whereas miR-155 inhibition in conventional CD4(+) Th cells strengthened nTreg cell-mediated suppression, overexpression of mature miR-155 rendered these cells unresponsive to nTreg cell-mediated suppression.

Conclusion: Investigation of FoxP3 downstream targets, certainly of bound and regulated miRNAs revealed the associated function between the master regulator FoxP3 and miRNAs as regulators itself. miR-155 is shown to be crucially involved in nTreg cell mediated tolerance by regulating the susceptibility of conventional human as well as murine CD4(+) Th cells to nTreg cell-mediated suppression.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0007158PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2743997PMC
September 2009

Tumor stroma marker endosialin (Tem1) is a binding partner of metastasis-related protein Mac-2 BP/90K.

FASEB J 2008 Aug 19;22(8):3059-67. Epub 2008 May 19.

Joint Research Division Vascular Biology of the Medical Faculty Mannheim, University of Heidelberg and the German Cancer Research Center, Heidelberg, Germany.

Tumor development involves complex bidirectional interactions between tumor cells and host stromal cells. Endosialin (Tem1) has been identified as a highly O-glycosylated transmembrane glycoprotein, which is specifically expressed by tumor vessel-associated pericytes and stromal fibroblasts of a wide range of human tumors. Recent experiments in endosialin-deficient mice have unraveled a critical role of endosialin in site-specific tumor progression and metastasis. To molecularly understand the mechanisms of endosialin function, we aimed to identify extracellular endosialin ligands and identified Mac-2 BP/90K as a specific interaction partner. Detailed biochemical analyses identified a C-terminal fragment of Mac-2 BP/90K, which was shown to contain binding sites for galectin-3, and collagens as the structures responsible for endosialin binding. Subsequent expression analysis of Mac-2 BP/90K in vivo revealed weak or no expression in most normal tissues and strong up-regulation in tumor cells of human neoplastic tissues. Intriguingly, the expression patterns of Mac-2 BP/90K and endosialin were mutually exclusive in all human tissues. Correspondingly, loss-of-function adhesion experiments of Mac-2 BP/90K-expressing tumor cells on endosialin-expressing fibroblasts revealed a repulsive outcome of the Mac-2 BP/90K interaction. Taken together, the experiments identify a novel repulsive interaction between endosialin on stromal fibroblasts and Mac-2 BP/90K on tumor cells.
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http://dx.doi.org/10.1096/fj.07-101386DOI Listing
August 2008

MicroRNA and proteome expression profiling in early-symptomatic α-synuclein(A30P)-transgenic mice.

Proteomics Clin Appl 2008 May 9;2(5):697-705. Epub 2008 Apr 9.

Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany.

The α-synuclein has been implicated in the pathophysiology of Parkinson's disease (PD), because mutations in the alpha-synuclein gene cause autosomal-dominant hereditary PD and fibrillary aggregates of alpha-synuclein are the major component of Lewy bodies. Since presynaptic accumulation of α-synuclein aggregates may trigger synaptic dysfunction and degeneration, we have analyzed alterations in synaptosomal proteins in early symptomatic α-synuclein(A30P)-transgenic mice by two-dimensional differential gel electrophoresis. Moreover, we carried out microRNA expression profiling using microfluidic chips, as microRNA have recently been shown to regulate synaptic plasticity in rodents and to modulate polyglutamine-induced protein aggregation and neurodegeneration in flies. Differentially expressed proteins in α-synuclein(A30P)-transgenic mice point to alterations in mitochondrial function, actin dynamics, iron transport, and vesicle exocytosis, thus partially resembling findings in PD patients. Oxygen consumption of isolated brain mitochondria, however, was not reduced in mutant mice. Levels of several microRNA (miR-10a, -10b, -212, -132, -495) were significantly altered. One of them (miR-132) has been reported to be highly inducible by growth factors and to be a key regulator of neurite outgrowth. Moreover, miR-132-recognition sequences were detected in the mRNA transcripts of two differentially expressed proteins. MicroRNA may thus represent novel biomarkers for neuronal malfunction and potential therapeutic targets for human neurodegenerative diseases.
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http://dx.doi.org/10.1002/prca.200780025DOI Listing
May 2008

Short-term intra-arterial infusion of monocyte chemoattractant protein-1 results in sustained collateral artery growth.

J Cardiovasc Pharmacol Ther 2007 Mar;12(1):61-8

Department of Cardiovascular Disease, Boehringer Ingelheim Pharmaceuticals Inc., 900 Ridgebury Road, Ridgefield, CT 06877, USA.

Monocyte chemoattractant protein-1 (MCP-1) is a stimulator of collateral artery growth and has been shown to increase collateral artery conductance in rabbits and pigs. The minimal infusion duration and the minimally effective dose of MCP-1 are currently unknown, as is the sustainability of the therapeutic effect over a longer observation period than tested before. MCP-1 was infused intra-arterially in pigs after unilateral femoral artery occlusion in different doses and infusion durations between 2 hours and 2 weeks. Two weeks after ligation, arterial conductance under maximal vasodilatation was measured. The long-term efficacy was investigated in 2 additional groups of animals after 6 weeks. Infusion with 2 microg/min of MCP-1 for 6 hours was sufficient to double arterial conductance, and arterial conductance after 6 weeks was still significantly increased.
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http://dx.doi.org/10.1177/1074248406298625DOI Listing
March 2007

FPRL-1 induces modifications of migration-associated proteins in human neutrophils.

Proteomics 2006 Sep;6(17):4790-9

Boehringer Ingelheim Pharma GmbH & Co. KG, Department of Respiratory Research, Genomics Group, Biberach an der Riss, Germany.

Human polymorphonuclear neutrophils (PMNs) are an important cell population of the innate immune system, which migrates following concentration gradients of chemokines or chemoattractants to locations of infection and inflammation in order to eliminate invading microorganisms and cell debris. For both migration and adhesion of PMNs to various tissues, the dynamic remodeling of the cytoskeleton is key prerequisite. In this context, the formyl peptide receptor-like 1 (FPRL-1) is an important chemoattractant receptor expressed on PMNs. In this study, we show that a short stimulation of FPRL-1 with either a synthetic peptide ligand (W-peptide) or a natural ligand (sCKbeta8-1) changes the protein pattern of PMNs as assessed by 2-D-DIGE. MS analysis of selected deregulated protein species resulted in the identification of proteins that are involved in the remodeling process of the actin- and tubulin-based cytoskeleton, such as L-plastin, moesin, cofilin, and stathmin. Subsequent validation experiments performed either by Western blotting or phosphoprotein-specific gel staining (Pro-Q Diamond) revealed that L-plastin is phosphorylated, whereas moesin, cofilin, and stathmin are dephosphorylated in PMNs upon FPRL-1 stimulation. These findings suggest that FPRL-1 signaling targets proteins that regulate the motility of PMNs and moreover show that 2-D-DIGE is a technique capable of detecting and quantifying differently modified (e.g., phosphorylated) protein variants.
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http://dx.doi.org/10.1002/pmic.200600121DOI Listing
September 2006

In vivo human MCP-1 transfection in porcine arteries by intravascular electroporation.

Pharm Res 2005 Oct 22;22(10):1685-91. Epub 2005 Sep 22.

Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, Connecticut, 06877, USA.

Purpose: The purpose of this study was to develop a nonviral gene transfer method for therapeutic delivery of the human monocyte chemoattractant protein-1 (MCP-1) in patients with peripheral artery disease, using local catheter-mediated electrotransfer of naked plasmid DNA into arteries.

Methods: Arterial walls of the A. profunda femoris of pigs were transfected either with a human MCP-1 or with a firefly luciferase-encoding DNA construct. The efficacy of electrotransfer of DNA was analyzed after 2 days by quantitative polymerase chain reaction (PCR) or luciferase activity measurements. To optimize MCP-1 gene transfer conditions, a voltage range of 60-150 V was applied as a train of six square pulses of 20 ms each at 1 Hz and was combined with a dose of 150 microg DNA. Subsequently, the optimized voltage was used to test a dose range of 80-300 microg DNA.

Results: The voltage optimum for arterial transfection was observed at 80 volts. Using this setting, the dose application of 300 microg MCP-1 plasmid DNA (the maximal dose tested) demonstrated the highest MCP-1 expression signal. The electric pulses and the transfer and expression of human MCP-1 per se did not induce endogenous porcine MCP-1 expression in treated arteries. Interestingly, angioplastic predilation of the artery before gene transfer, which had originally been postulated to enhance transfection by improving access of the plasmid to subendothelial cell layers, resulted in an attenuated transfection efficacy.

Conclusions: The present study demonstrates that transluminal catheter-based electroporation provides an efficient technology for nonviral intravascular gene transfer by just applying unformulated DNA.
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http://dx.doi.org/10.1007/s11095-005-6334-9DOI Listing
October 2005

Proteomic study of human bronchoalveolar lavage fluids from smokers with chronic obstructive pulmonary disease by combining surface-enhanced laser desorption/ionization-mass spectrometry profiling with mass spectrometric protein identification.

Proteomics 2005 Jul;5(11):2972-80

Department of Pulmonary Research, Genomics Group, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany.

Bronchoalveolar lavage fluid (BALF) is an important diagnostic source to investigate cellular and molecular changes in the course of lung disorders. The pattern of soluble proteins in BALF obtained from patients at different stages of respiratory disorders may provide deeper insights in the molecular mechanisms of the disease. We used surface-enhanced laser desorption/ionization mass spectrometry (MS) for differential protein display combined with reversed-phase chromatography and subsequent matrix-assisted laser desorption/ionization-MS or nanoliquid chromatography MS/MS analysis for protein identification to compare the protein pattern of BALF samples obtained from ten smokers suffering from chronic obstructive pulmonary disease (COPD), eight clinically asymptomatic smokers, and eight nonsmokers without pulmonary disease. In this context, we were able to identify small proteins and peptides, either differentially expressed or secreted in the course of COPD or in a direct response to cigarette smoke. The concentrations of neutrophil defensins 1 and 2, S100A8 (calgranulin A), and S100A9 (calgranulin B) were elevated in BALFs of smokers with COPD when compared to asymptomatic smokers. Increased concentrations in S100A8 (Calgranulin A), salivary proline-rich peptide P-C, and lysozyme C were detected in BALFs of asymptomatic smokers when compared to nonsmokers, whereas salivary proline-rich peptide P-D and Clara cell phospholipid-binding protein (CC10) were reduced in their concentration. The identified proteins and peptides might be useful in the future as diagnostic markers for smoke-induced lung irritations and COPD.
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http://dx.doi.org/10.1002/pmic.200401180DOI Listing
July 2005

Human primary co-culture angiogenesis assay reveals additive stimulation and different angiogenic properties of VEGF and HGF.

Cytokine 2004 May;26(4):178-85

Department of Non-clinical Drug Safety, Molecular & Cell Toxicology Group, Boehringer Ingelheim Pharma GmbH & Co. KG. Birkendorfer Strasse 65, D-88397 Biberach, Germany.

Therapeutic angiogenesis aims to induce blood vessel growth in acute or chronic ischemic tissues and has gained tremendous interest over the last years. To study factors and combinations thereof that potentially induce or modify angiogenesis and to evaluate their therapeutic potential, various in vitro assays have been developed. Although endothelial cells have attracted most attention in these assays, they alone cannot complete vessel maturation since extracellular matrix (ECM) components and mesenchymal cells also play an important role in vascular development. To address this complexity we focussed on a human co-culture angiogenesis assay comprising primary endothelial cells as well as primary ECM-producing fibroblasts. In this assay HGF and VEGF as single factors and combined were tested for the potential to induce an angiogenic response, which was detected by image analysis assessing the area, length and branches of the formed vascular structures. The results show that the cytokines HGF and VEGF both promote angiogenesis in this co-culture assay by inducing distinguishable patterns of vascular structures. VEGF increases the length, area and branch point number of induced vessels whereas HGF mediates exclusively vascular area growth resulting in vascular structures of enlarged diameter. Moreover, the combination of both cytokines results in an additive increase of vascular diameter.
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http://dx.doi.org/10.1016/j.cyto.2004.03.003DOI Listing
May 2004

Stabilized nonviral formulations for the delivery of MCP-1 gene into cells of the vasculoendothelial system.

Pharm Res 2004 Apr;21(4):683-91

Boehringer Ingelheim Pharma GmbH & Co. KG, GFB F&E Germany, Genomics & Proteomics Group, D-88397 Biberach an der Riss, Germany.

Purpose: The purpose of this study was to develop a stabilized non-viral gene transfer system for the efficient delivery and expression of monocyte chemoattractant protein 1 (MCP-1) gene in cells of the vasculoendothelial system.

Methods: Plasmid DNA was condensed with polyethylenimine (PEI), conjugates of PEI with polyethylene glycol (PEG), and PEI conjugates with the membrane-active peptide melittin. Surface charge and particle size of the resulting gene transfer particles were analyzed by laser light scattering. Reporter gene studies and toxicity assays were conducted on smooth muscle cells and endothelial cells of human, porcine, or rat origin.

Results: Nonviral gene carriers containing PEI and PEG were developed that could be produced in batches of several milligrams and conveniently stored as frozen samples. Incorporation of PEG into the transfection complex significantly reduced cellular toxicity. The cryoconserved gene transfer particles mediated high expression of luciferase, enhanced green fluorescent protein (EGFP), or secreted alkaline phosphatase reporter genes. Highest reporter gene expression was achieved with PEI polyplexes containing PEG and melittin. The gene for MCP-1 was efficiently delivered into target cells and resulted in expression of up to 125 ng/ml secreted bioactive MCP-1 protein per 50,000 cells.

Conclusions: Gene carriers based on PEI and PEG display reduced toxicity, can be stored in frozen form without loss of biological activity, and can efficiently transfect cells of the vasculoendothelial system. Such gene carriers hold a potential for use in arterial gene transfer and local secretion of MCP-1 as trigger of therapeutic arteriogenesis in arterial occlusion diseases.
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http://dx.doi.org/10.1023/b:pham.0000022416.33048.81DOI Listing
April 2004