Sabine M Hölter | Technical University of Munich (original) (raw)

Papers by Sabine M Hölter

eLife

While high risk of failure is an inherent part of developing innovative therapies, it can be redu... more While high risk of failure is an inherent part of developing innovative therapies, it can be reduced by adherence to evidence-based rigorous research practices. Supported through the European Union’s Innovative Medicines Initiative, the EQIPD consortium has developed a novel preclinical research quality system that can be applied in both public and private sectors and is free for anyone to use. The EQIPD Quality System was designed to be suited to boost innovation by ensuring the generation of robust and reliable preclinical data while being lean, effective and not becoming a burden that could negatively impact the freedom to explore scientific questions. EQIPD defines research quality as the extent to which research data are fit for their intended use. Fitness, in this context, is defined by the stakeholders, who are the scientists directly involved in the research, but also their funders, sponsors, publishers, research tool manufacturers, and collaboration partners such as peers i...

Translational Psychiatry

Neurodevelopmental disorders are heterogeneous and identifying shared genetic aetiologies and con... more Neurodevelopmental disorders are heterogeneous and identifying shared genetic aetiologies and converging signalling pathways affected could improve disease diagnosis and treatment. Truncating mutations of the abnormal spindle-like microcephaly associated (ASPM) gene cause autosomal recessive primary microcephaly (MCPH) in humans. ASPM is a positive regulator of Wnt/β-Catenin signalling and controls symmetric to asymmetric cell division. This process balances neural progenitor proliferation with differentiation during embryogenesis, the malfunction of which could interfere with normal brain development. ASPM mutations may play a role also in other neurodevelopmental disorders, nevertheless, we lack the details of how or to what extent. We therefore assessed neurodevelopmental disease and circuit endophenotypes in mice with a truncating Aspm 1-7 mutation. Aspm 1-7 mice exhibited impaired short-and long-term object recognition memory and markedly enhanced place learning in the IntelliCage®. This behaviour pattern is reminiscent of a cognitive phenotype seen in mouse models and patients with a rare form of autism spectrum disorder (ASD) as well as in mouse models of altered Wnt signalling. These alterations were accompanied by ventriculomegaly, corpus callosum dysgenesis and decreased parvalbumin (PV)+ interneuron numbers in the hippocampal Cornu Ammonis (CA) region and thalamic reticular nucleus (TRN). PV+ cell number correlated to object recognition (CA and TRN) and place learning (TRN). This opens the possibility that, as well as causing MCPH, mutant ASPM potentially contributes to other neurodevelopmental disorders such as ASD through altered parvalbuminergic interneuron development affecting cognitive behaviour. These findings provide important information for understanding the genetic overlap and improved treatment of neurodevelopmental disorders associated with ASPM.

Mammalian Genome

The collaborative cross (CC) is a large panel of mouse-inbred lines derived from eight founder st... more The collaborative cross (CC) is a large panel of mouse-inbred lines derived from eight founder strains (NOD/ShiLtJ, NZO/HILtJ, A/J, C57BL/6J, 129S1/SvImJ, CAST/EiJ, PWK/PhJ, and WSB/EiJ). Here, we performed a comprehensive and comparative phenotyping screening to identify phenotypic differences and similarities between the eight founder strains. In total, more than 300 parameters including allergy, behavior, cardiovascular, clinical blood chemistry, dysmorphology, bone and cartilage, energy metabolism, eye and vision, immunology, lung function, neurology, nociception, and pathology were analyzed; in most traits from sixteen females and sixteen males. We identified over 270 parameters that were significantly different between strains. This study highlights the value of the founder and CC strains for phenotype-genotype associations of many genetic traits that are highly relevant to human diseases. All data described here are publicly available from the mouse phenome database for analy...

Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease

Isolated methylmalonic aciduria (MMAuria) is primarily caused by deficiency of methylmalonyl-CoA ... more Isolated methylmalonic aciduria (MMAuria) is primarily caused by deficiency of methylmalonyl-CoA mutase (MMUT or MUT). Biochemically, MUT deficiency results in the accumulation of methylmalonic acid (MMA), propionyl-carnitine (C3) and other metabolites. Patients often exhibit lethargy, failure to thrive and metabolic decompensation leading to coma or even death, with kidney and neurological impairment frequently identified in the long-term. Here, we report a hemizygous mouse model which combines a knock-in (ki) missense allele of Mut with a knockout (ko) allele (Mut-ko/ki mice) that was fed a 51%-protein diet from day 12 of life, constituting a bespoke model of MMAuria. Under this diet, mutant mice developed a pronounced metabolic phenotype characterized by drastically increased blood levels of MMA and C3 compared to their littermate controls (Mut-ki/wt). With this bespoke mouse model, we performed a standardized phenotypic screen to assess the whole-body impairments associated with this strong metabolic condition. We found that Mut-ko/ki mice show common clinical manifestations of MMAuria, including pronounced failure to thrive, indications of mild neurological and kidney dysfunction, and degenerative morphological changes in the liver, along with less well described symptoms such as cardiovascular and hematological abnormalities. The analyses also reveal so far unknown disease characteristics, including low bone mineral density, anxiety-related behaviour and ovarian atrophy. This first phenotypic screening of a MMAuria mouse model confirms its relevance to human disease, reveals new alterations associated with MUT deficiency, and suggests a series of quantifiable readouts that can be used to evaluate potential treatment strategies.

Experimental Eye Research

Mutation in the mouse histone gene Hist2h3c1 leads to degeneration of the lens vesicle and severe... more Mutation in the mouse histone gene Hist2h3c1 leads to degeneration of the lens vesicle and severe microphthalmia

Disease models & mechanisms, Aug 23, 2017

MEIS1 is a developmental transcription factor linked to restless legs syndrome (RLS) in genome-wi... more MEIS1 is a developmental transcription factor linked to restless legs syndrome (RLS) in genome-wide association studies. RLS is a movement disorder leading to severe sleep reduction and with significant impact on the quality-of-life of patients. In genome-wide association studies, MEIS1 has consistently been the gene with the highest effect size and functional studies suggest a disease-relevant downregulation. Therefore, haploinsufficiency of Meis1 could be the most potential system for modeling RLS in animals. We used heterozygous Meis1 knock-out mice to study the effects of Meis1 haploinsufficiency on mouse behavioral and neurological phenotypes, and to relate the findings to human RLS. We exposed the Meis1-deficient mice to assays of motor, sensorimotor and cognitive ability and assessed the effect of a dopaminergic receptor 2/3 agonist commonly used in the treatment of RLS. The mutant mice showed a pattern of circadian hyperactivity, compatible with human RLS. Moreover, we disco...

Journal of neuroscience methods, Jan 5, 2017

Generation and phenotyping of mutant mouse models continues to increase along with the search for... more Generation and phenotyping of mutant mouse models continues to increase along with the search for the most efficient phenotyping tests. Here we asked if a combination of different locomotor tests is necessary for comprehensive locomotor phenotyping, or if a large data set from an automated gait analysis with the CatWalk system would suffice. First we endeavored to meaningfully reduce the large CatWalk data set by Principal Component Analysis (PCA) to decide on the most relevant parameters. We analyzed the influence of sex, body weight, genetic background and age. Then a combination of different locomotor tests was analyzed to investigate the possibility of redundancy between tests. The extracted 10 components describe 80% of the total variance in the CatWalk, characterizing different aspects of gait. With these, effects of CatWalk version, sex, body weight, age and genetic background were detected. In addition, the PCA on a combination of locomotor tests suggests that these are inde...

Neuron, Jan 2, 2017

Precise regulation of cellular metabolism is hypothesized to constitute a vital component of the ... more Precise regulation of cellular metabolism is hypothesized to constitute a vital component of the developmental sequence underlying the life-long generation of hippocampal neurons from quiescent neural stem cells (NSCs). The identity of stage-specific metabolic programs and their impact on adult neurogenesis are largely unknown. We show that the adult hippocampal neurogenic lineage is critically dependent on the mitochondrial electron transport chain and oxidative phosphorylation machinery at the stage of the fast proliferating intermediate progenitor cell. Perturbation of mitochondrial complex function by ablation of the mitochondrial transcription factor A (Tfam) reproduces multiple hallmarks of aging in hippocampal neurogenesis, whereas pharmacological enhancement of mitochondrial function ameliorates age-associated neurogenesis defects. Together with the finding of age-associated alterations in mitochondrial function and morphology in NSCs, these data link mitochondrial complex f...

Nucleic acids research, Jan 6, 2016

An interplay between the nucleosome binding proteins H1 and HMGN is known to affect chromatin dyn... more An interplay between the nucleosome binding proteins H1 and HMGN is known to affect chromatin dynamics, but the biological significance of this interplay is still not clear. We find that during embryonic stem cell differentiation loss of HMGNs leads to down regulation of genes involved in neural differentiation, and that the transcription factor OLIG2 is a central node in the affected pathway. Loss of HMGNs affects the expression of OLIG2 as well as that of OLIG1, two transcription factors that are crucial for oligodendrocyte lineage specification and nerve myelination. Loss of HMGNs increases the chromatin binding of histone H1, thereby recruiting the histone methyltransferase EZH2 and elevating H3K27me3 levels, thus conferring a repressive epigenetic signature at Olig1&2 sites. Embryonic stem cells lacking HMGNs show reduced ability to differentiate towards the oligodendrocyte lineage, and mice lacking HMGNs show reduced oligodendrocyte count and decreased spinal cord myelination,...

Frontiers in Behavioral Neuroscience, 2015

Adult neurogenesis occurs in the adult mammalian subventricular zone (SVZ) along the walls of the... more Adult neurogenesis occurs in the adult mammalian subventricular zone (SVZ) along the walls of the lateral ventricles and the subgranular zone (SGZ) of the hippocampal dentate gyrus. While a burgeoning body of research implicates adult neurogenesis in olfactory bulb (OB)-and hippocampal-related behaviors, the precise function continues to elude. To further assess the behavioral importance of adult neurogenesis, we herein generated a novel inducible transgenic mouse model of adult neurogenesis reduction where mice with CreER T2 under doublecortin (DCX) promoter control were crossed with mice where diphtheria toxin A (DTA) was driven by the Rosa26 promoter. Activation of DTA, through the administration of tamoxifen (TAM), results in a specific reduction of DCX+ immature neurons in both the hippocampal dentate gyrus and OB. We show that the decrease of DCX+ cells causes impaired social discrimination ability in both young adult (from 3 months) and middle aged (from 10 months) mice. Furthermore, these animals showed an age-independent altered coping behavior in the Forced Swim Test without clear changes in anxiety-related behavior. Notably, these behavior changes were reversible on repopulating the neurogenic zones with DCX+ cells on cessation of the TAM treatment, demonstrating the specificity of this effect. Overall, these results support the notion that adult neurogenesis plays a role in social memory and in stress coping but not necessarily in anxiety-related behavior.

Nature genetics, Jan 27, 2015

The function of the majority of genes in the mouse and human genomes remains unknown. The mouse e... more The function of the majority of genes in the mouse and human genomes remains unknown. The mouse embryonic stem cell knockout resource provides a basis for the characterization of relationships between genes and phenotypes. The EUMODIC consortium developed and validated robust methodologies for the broad-based phenotyping of knockouts through a pipeline comprising 20 disease-oriented platforms. We developed new statistical methods for pipeline design and data analysis aimed at detecting reproducible phenotypes with high power. We acquired phenotype data from 449 mutant alleles, representing 320 unique genes, of which half had no previous functional annotation. We captured data from over 27,000 mice, finding that 83% of the mutant lines are phenodeviant, with 65% demonstrating pleiotropy. Surprisingly, we found significant differences in phenotype annotation according to zygosity. New phenotypes were uncovered for many genes with previously unknown function, providing a powerful basis...

Developmental Cell, 2015

Highlights d MIM deforms plasma membrane into proto-protrusions that initiate spine formation d P... more Highlights d MIM deforms plasma membrane into proto-protrusions that initiate spine formation d PIP 2 promotes MIM recruitment and subsequent Arp2/3mediated actin assembly d MIM deficiency decreases and overexpression of MIM increases spine density d Loss of MIM in mice results in aberrant synaptic transmission and behavior

Behavioural pharmacology, 1998

In order to study the dynamics of ethanol drinking behaviour, male Wistar rats were given the fre... more In order to study the dynamics of ethanol drinking behaviour, male Wistar rats were given the free choice between tap water, and 5, 10 and 20% ethanol solutions. After 8 weeks of continuous access, the animals were repeatedly deprived of the ethanol solutions for 3 days every 4 weeks. In the first experiment, drinking patterns were recorded for 24 h with an electronic drinkometer device, at different time-points of ethanol experience and after an ethanol deprivation episode. The preference for more highly concentrated ethanol solutions as well as ethanol consumption increased with continuing ethanol experience. Furthermore, after the ethanol deprivation episode, the animals immediately and preferentially drank from the 20% ethanol solution, the most highly concentrated ethanol solution offered. Additionally, the number of drinking bouts, particularly at the 10 and 20% ethanol solutions, was increased during the first hour after ethanol re-presentation. In a second experiment, the ef...

Communicative & Integrative Biology, 2009

R. cGMP-dependent protein kinase type I is implicated in the regulation of the timing and quality... more R. cGMP-dependent protein kinase type I is implicated in the regulation of the timing and quality of sleep and wakefulness.

Encyclopedia of Psychopharmacology, 2010

PLoS ONE, 2014

Iron Regulatory Protein 2 (Irp2, Ireb2) is a central regulator of cellular iron homeostasis in ve... more Iron Regulatory Protein 2 (Irp2, Ireb2) is a central regulator of cellular iron homeostasis in vertebrates. Two global knockout mouse models have been generated to explore the role of Irp2 in regulating iron metabolism. While both mouse models show that loss of Irp2 results in microcytic anemia and altered body iron distribution, discrepant results have drawn into question the role of Irp2 in regulating brain iron metabolism. One model shows that aged Irp2 deficient mice develop adultonset progressive neurodegeneration that is associated with axonal degeneration and loss of Purkinje cells in the central nervous system. These mice show iron deposition in white matter tracts and oligodendrocyte soma throughout the brain. A contrasting model of global Irp2 deficiency shows no overt or pathological signs of neurodegeneration or brain iron accumulation, and display only mild motor coordination and balance deficits when challenged by specific tests. Explanations for conflicting findings in the severity of the clinical phenotype, brain iron accumulation and neuronal degeneration remain unclear. Here, we describe an additional mouse model of global Irp2 deficiency. Our aged Irp2 2/2 mice show marked iron deposition in white matter and in oligodendrocytes while iron content is significantly reduced in neurons. Ferritin and transferrin receptor 1 (TfR1, Tfrc), expression are increased and decreased, respectively, in the brain from Irp2 2/2 mice. These mice show impairments in locomotion, exploration, motor coordination/balance and nociception when assessed by neurological and behavioral tests, but lack overt signs of neurodegenerative disease. Ultrastructural studies of specific brain regions show no evidence of neurodegeneration. Our data suggest that Irp2 deficiency dysregulates brain iron metabolism causing cellular dysfunction that ultimately leads to mild neurological, behavioral and nociceptive impairments.

To the editor: To overcome the bottleneck of standardized, comprehensive phenotyping 1,2 in mouse... more To the editor: To overcome the bottleneck of standardized, comprehensive phenotyping 1,2 in mouse genetics, we established within the National Genome Research Network (NGFN), and in collaboration with the pan-European consortium EUMORPHIA, a unique mouse phenotyping center (German Mouse Clinic, GMC) with open access to the scientific community. The production of mutant mouse lines (MMLs) by gene knockout and transgenic technology or by mutagenesis generates a large collection of models for in vivo analysis of distinct gene functions, many of them potentially providing models for the study of human diseases 3-6. But full and efficient use of this large resource is now hindered by shortcomings in the quality and extent of the phenotypic analysis. In the GMC, experts from various fields of mouse physiology and pathology in close cooperation with clinicians work side by side at one location. The facilities of the GMC were designed to provide an optimized specific pathogen-free (SPF) infrastructure with individual units (laboratories and adjacent mouse rooms) for each screen. The examinations comprise the following areas: allergy, behavior, clinical chemistry, dysmorphology, energy metabolism, eye development and vision, host-pathogen interactions, immunology, lung function, molecular phenotyping, neurology, nociception, and pathology (Supplementary Fig. 1 online). Screens for cardiovascular analyses and steroid metabolism were recently implemented. Additional units are designated to accommodate guest scientists for collaborative work, especially for the transfer of standardized protocols to other laboratories. MMLs entering the GMC are first examined in a comprehensive and standardized primary screen (approximately 240 different parameters per individual mouse). Therefore, an innovative workflow had to be established, allowing a series of noninvasive tests on the same cohort of animals without major interferences between individual examinations. A single passage of a group of 30 mutant mice in comparison to the same number of age-and sex-matched littermate controls provides a detailed picture about the complexity of the MML-related phenotype. Up to 26 MMLs can be analyzed in the primary screen per year. In particular the permanent active collaborations among experts in different fields have turned out to be the key factor for the effective and interdisciplinary characterization of MMLs. Standard operation procedures for all tests in the primary screening have been established and validated, and the GMC has been running for more than one year at its full capacity. Our experiences confirm the feasibility of the general concept of high-throughput mouse phenotyping, and for almost all lines, even well-known MMLs, new phenotypes were identified (715 parameters were found to be altered in 23 MMLs). The GMC is an open-access technology platform, allowing all scientists worldwide to submit their MMLs for comprehensive phenotyping. A web-based application procedure for mouse import was established. All experiments are performed on a collaborative basis between the mouse provider and the GMC. Additional information and a description of the application procedures are available (http://www.mouseclinic.de). Note: Supplementary information is available on the Nature Methods website.

Methods in Molecular Biology, 2009

With the completion of the mouse genome sequence an essential task for biomedical sciences in the... more With the completion of the mouse genome sequence an essential task for biomedical sciences in the twenty-first century will be the generation and functional analysis of mouse models for every gene in the mammalian genome. More than 30,000 mutations in ES cells will be engineered and thousands of mouse disease models will become available over the coming years by the collaborative effort of the International Mouse Knockout Consortium. In order to realize the full value of the mouse models proper characterization, archiving and dissemination of mouse disease models to the research community have to be performed. Phenotyping centers (mouse clinics) provide the necessary capacity, broad expertise, equipment, and infrastructure to carry out large-scale systemic first-line phenotyping. Using the example of the German Mouse Clinic (GMC) we will introduce the reader to the different aspects of the organization of a mouse clinic and present selected methods used in first-line phenotyping.