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Fabry disease is an X-linked lysosomal storage disorder due to impaired activity of alpha-galactosidase A with intracellular accumulation of globotriaosylceramide. Associated small fiber pathology leads to characteristic pain in Fabry disease. We systematically assessed sensory system, physical activity, metabolic parameters, and morphology of male and female mice with alpha-galactosidase A deficiency (Fabry ko) from 2 to 27 months of age and compared results with those of age- and gender-matched wild-type littermates of C57Bl/6J background. Results From the age of two months, male and female Fabry mice showed mechanical hypersensitivity (p < 0.001 each) compared to wild-type littermates. Young Fabry ko mice of both genders were hypersensitive to heat stimulation (p < 0.01) and developed heat hyposensitivity with aging (p < 0.05), while cold hyposensitivity was present constantly in young (p < 0.01) and old (p < 0.05) Fabry ko mice compared to wild-type littermates. Stride angle increased only in male Fabry ko mice with aging (p < 0.01) in comparison to wild-type littermates. Except for young female mice, male (p < 0.05) and female (p < 0.01) Fabry ko mice had a higher body weight than wild-type littermates. Old male Fabry ko mice were physically less active than their wild-type littermates (p < 0.05), had lower chow intake (p < 0.001), and lost more weight (p < 0.001) in a one-week treadmill experiment than wild-type littermates. Also, Fabry ko mice showed spontaneous pain protective behavior and developed orofacial dysmorphism resembling patients with Fabry disease.
Conclusions. Mice with alpha-galactosidase A deficiency show age-dependent and distinct deficits of the sensory system. alpha-galactosidase A-deficient mice seem to model human Fabry disease and may be helpful when studying the pathophysiology of Fabry-associated pain.
Oligodendrocytes are the myelinating glia of the central nervous system and ensure rapid saltatory conduction. Shortage or loss of these cells leads to severe malfunctions as observed in human leukodystrophies and multiple sclerosis, and their replenishment by reprogramming or cell conversion strategies is an important research aim. Using a transgenic approach we increased levels of the transcription factor Sox10 throughout the mouse embryo and thereby prompted Fabp7-positive glial cells in dorsal root ganglia of the peripheral nervous system to convert into cells with oligodendrocyte characteristics including myelin gene expression. These rarely studied and poorly characterized satellite glia did not go through a classic oligodendrocyte precursor cell stage. Instead, Sox10 directly induced key elements of the regulatory network of differentiating oligodendrocytes, including Olig2, Olig1, Nkx2.2 and Myrf. An upstream enhancer mediated the direct induction of the Olig2 gene. Unlike Sox10, Olig2 was not capable of generating oligodendrocyte-like cells in dorsal root ganglia. Our findings provide proof-of-concept that Sox10 can convert conducive cells into oligodendrocyte-like cells in vivo and delineates options for future therapeutic strategies.
α-Synuclein is a protein implicated in the etiopathogenesis of Parkinson’s disease (PD). AAV1/2-driven overexpression of human mutated A53T-α-synuclein in rat and monkey substantia nigra (SN) induces degeneration of nigral dopaminergic neurons and decreases striatal dopamine and tyrosine hydroxylase (TH). Given certain advantages of the mouse, especially it being amendable to genetic manipulation, translating the AAV1/2-A53T α-synuclein model to mice would be of significant value. AAV1/2-A53T α-synuclein or AAV1/2 empty vector (EV) at a concentration of 5.16 x 10\(^{12}\) gp/ml were unilaterally injected into the right SN of male adult C57BL/6 mice. Post-mortem examinations included immunohistochemistry to analyze nigral α-synuclein, Ser129 phosphorylated α-synuclein and TH expression, striatal dopamine transporter (DAT) levels by autoradiography and dopamine levels by high performance liquid chromatography. At 10 weeks, in AAV1/2-A53T α-synuclein mice there was a 33% reduction in TH+ dopaminergic nigral neurons (P < 0.001), 29% deficit in striatal DAT binding (P < 0.05), 38% and 33% reductions in dopamine (P < 0.001) and DOPAC (P < 0.01) levels and a 60% increase in dopamine turnover (homovanilic acid/dopamine ratio; P < 0.001). Immunofluorescence showed that the AAV1/2-A53T α-synuclein injected mice had widespread nigral and striatal expression of vector-delivered A53T-α-synuclein. Concurrent staining with human PD SN samples using gold standard histological methodology for Lewy pathology detection by proteinase K digestion and application of specific antibody raised against human Lewy body α-synuclein (LB509) and Ser129 phosphorylated α-synuclein (81A) revealed insoluble α-synuclein aggregates in AAV1/2-A53T α-synuclein mice resembling Lewy-like neurites and bodies. In the cylinder test, we observed significant paw use asymmetry in the AAV1/2-A53T α-synuclein group when compared to EV controls at 5 and 9 weeks post injection (P < 0.001; P < 0.05). These data show that unilateral injection of AAV1/2-A53T α-synuclein into the mouse SN leads to persistent motor deficits, neurodegeneration of the nigrostriatal dopaminergic system and development of Lewy-like pathology, thereby reflecting clinical and pathological hallmarks of human PD.
Oncolytic vaccinia virus (VACV) therapy is an alternative cancer treatment modality that mediates targeted tumor destruction through a tumor-selective replication and an induction of anti-tumor immunity. We developed a humanized tumor mouse model with subcutaneous human tumors to analyze the interactions of VACV with the developing tumors and human immune system. A successful systemic reconstitution with human immune cells including functional T cells as well as development of tumors infiltrated with human T and natural killer (NK) cells was observed. We also demonstrated successful in vivo colonization of such tumors with systemically administered VACVs. Further, a new recombinant GLV-1h376 VACV encoding for a secreted human CTLA4-blocking single-chain antibody (CTLA4 scAb) was tested. Surprisingly, although proving CTLA4 scAb’s in vitro binding ability and functionality in cell culture, beside the significant increase of CD56\(^{bright}\) NK cell subset, GLV-1h376 was not able to increase cytotoxic T or overall NK cell levels at the tumor site. Importantly, the virus-encoded β-glucuronidase as a measure of viral titer and CTLA4 scAb amount was demonstrated. Therefore, studies in our “patient-like” humanized tumor mouse model allow the exploration of newly designed therapy strategies considering the complex relationships between the developing tumor, the oncolytic virus, and the human immune system.
The skeleton is a preferred homing site for breast cancer metastasis. To date, treatment options for patients with bone metastases are mostly palliative and the disease is still incurable. Indeed, key mechanisms involved in breast cancer osteotropism are still only partially understood due to the lack of suitable animal models to mimic metastasis of human tumor cells to a human bone microenvironment. In the presented study, we investigate the use of a human tissue-engineered bone construct to develop a humanized xenograft model of breast cancer-induced bone metastasis in a murine host. Primary human osteoblastic cell-seeded melt electrospun scaffolds in combination with recombinant human bone morphogenetic protein 7 were implanted subcutaneously in non-obese diabetic/severe combined immunodeficient mice. The tissue-engineered constructs led to the formation of a morphologically intact 'organ' bone incorporating a high amount of mineralized tissue, live osteocytes and bone marrow spaces. The newly formed bone was largely humanized, as indicated by the incorporation of human bone cells and human-derived matrix proteins. After intracardiac injection, the dissemination of luciferase-expressing human breast cancer cell lines to the humanized bone ossicles was detected by bioluminescent imaging. Histological analysis revealed the presence of metastases with clear osteolysis in the newly formed bone. Thus, human tissue-engineered bone constructs can be applied efficiently as a target tissue for human breast cancer cells injected into the blood circulation and replicate the osteolytic phenotype associated with breast cancer-induced bone lesions. In conclusion, we have developed an appropriate model for investigation of species-specific mechanisms of human breast cancer-related bone metastasis in vivo.
Fabry disease (FD) is a rare life-threatening disorder caused by deficiency of the alpha-galactosidase A (GLA) enzyme with a characteristic pain phenotype. Impaired GLA production or function leads to the accumulation of the cell membrane compound globotriaosylceramide (Gb3) in the neurons of the dorsal root ganglia (DRG) of FD patients. Applying immunohistochemistry (IHC) and quantitative real-time polymerase chain reaction (qRT PCR) analysis on DRG tissue of the GLA knockout (KO) mouse model of FD, we address the question of how Gb3 accumulation may contribute to FD pain and focus on the immune system and pain-associated ion channel gene expression. We show a higher Gb3 load in the DRG of young (<6 months) (p < 0.01) and old (≥12 months) (p < 0.001) GLA KO mice compared to old wildtype (WT) littermates, and an overall suppressed immune response in the DRG of old GLA KO mice, represented by a reduced number of CD206\(^+\) macrophages (p < 0.01) and lower gene expression levels of the inflammation-associated targets interleukin(IL)1b (p < 0.05), IL10 (p < 0.001), glial fibrillary acidic protein (GFAP) (p < 0.05), and leucine rich alpha-2-glycoprotein 1 (LRG1) (p < 0.01) in the DRG of old GLA KO mice compared to old WT. Dysregulation of immune-related genes may be linked to lower gene expression levels of the pain-associated ion channels calcium-activated potassium channel 3.1 (KCa3.1) and transient receptor potential ankyrin 1 channel (TRPA1). Ion channel expression might further be disturbed by impaired sphingolipid recruitment mediated via the lipid raft marker flotillin-1 (FLOT1). This impairment is represented by an increased number of FLOT1\(^+\) DRG neurons with a membranous expression pattern in old GLA KO mice compared to young GLA KO, young WT, and old WT mice (p < 0.001 each). Further, we provide evidence for aberrant behavior of GLA KO mice, which might be linked to dysregulated ion channel gene expression levels and disturbed FLOT1 distribution patterns. Behavioral testing revealed mechanical hypersensitivity in young (p < 0.01) and old (p < 0.001) GLA KO mice compared to WT, heat hypersensitivity in young GLA KO mice (p < 0.001) compared to WT, age-dependent heat hyposensitivity in old GLA KO mice (p < 0.001) compared to young GLA KO mice, and cold hyposensitivity in young (p < 0.001) and old (p < 0.001) GLA KO mice compared to WT, which well reflects the clinical phenotype observed in FD patients.
Mutations in GlyR α1 or β subunit genes in humans and rodents lead to severe startle disease characterized by rigidity, massive stiffness and excessive startle responses upon unexpected tactile or acoustic stimuli. The recently characterized startle disease mouse mutant shaky carries a missense mutation (Q177K) in the β8-β9 loop within the large extracellular N-terminal domain of the GlyR α1 subunit. This results in a disrupted hydrogen bond network around K177 and faster GlyR decay times. Symptoms in mice start at postnatal day 14 and increase until premature death of homozygous shaky mice around 4–6 weeks after birth. Here we investigate the in vivo functional effects of the Q177K mutation using behavioral analysis coupled to protein biochemistry and functional assays. Western blot analysis revealed GlyR α1 subunit expression in wild-type and shaky animals around postnatal day 7, a week before symptoms in mutant mice become obvious. Before 2 weeks of age, homozygous shaky mice appeared healthy and showed no changes in body weight. However, analysis of gait and hind-limb clasping revealed that motor coordination was already impaired. Motor coordination and the activity pattern at P28 improved significantly upon diazepam treatment, a pharmacotherapy used in human startle disease. To investigate whether functional deficits in glycinergic neurotransmission are present prior to phenotypic onset, we performed whole-cell recordings from hypoglossal motoneurons (HMs) in brain stem slices from wild-type and shaky mice at different postnatal stages. Shaky homozygotes showed a decline in mIPSC amplitude and frequency at P9-P13, progressing to significant reductions in mIPSC amplitude and decay time at P18-24 compared to wild-type littermates. Extrasynaptic GlyRs recorded by bath-application of glycine also revealed reduced current amplitudes in shaky mice compared to wild-type neurons, suggesting that presynaptic GlyR function is also impaired. Thus, a distinct, but behaviorally ineffective impairment of glycinergic synapses precedes the symptoms onset in shaky mice. These findings extend our current knowledge on startle disease in the shaky mouse model in that they demonstrate how the progression of GlyR dysfunction causes, with a delay of about 1 week, the appearance of disease symptoms.
Genome wide association meta-analysis identified ST3GAL3, a gene encoding the beta-galactosidase-alpha-2,3-sialyltransferase-III, as a risk gene for attention-deficit/hyperactivity disorder (ADHD). Although loss-of-function mutations in ST3GAL3 are implicated in non-syndromic autosomal recessive intellectual disability (NSARID) and West syndrome, the impact of ST3GAL3 haploinsufficiency on brain function and the pathophysiology of neurodevelopmental disorders (NDDs), such as ADHD, is unknown. Since St3gal3 null mutant mice display severe developmental delay and neurological deficits, we investigated the effects of partial inactivation of St3gal3 in heterozygous (HET) knockout (St3gal3±) mice on behavior as well as expression of markers linked to myelination processes and sialylation pathways. Our results reveal that male St3gal3 HET mice display cognitive deficits, while female HET animals show increased activity, as well as increased cognitive control, compared to their wildtype littermates. In addition, we observed subtle alterations in the expression of several markers implicated in oligodendrogenesis, myelin formation, and protein sialylation as well as cell adhesion/synaptic target glycoproteins of ST3GAL3 in a brain region- and/or sex-specific manner. Taken together, our findings indicate that haploinsufficiency of ST3GAL3 results in a sex-dependent alteration of cognition, behavior and markers of brain plasticity.
Optical in vivo imaging methods have advanced the fields of stem cell transplantation, graft-versus–host disease and graft-versus-tumor responses. Two well known optical methods, based on the transmission of light through the test animal are bioluminescence imaging (BLI) and fluorescence imaging (FLI). Both methods allow whole body in vivo imaging of the same animal over an extended time span where the cell distribution and proliferation can be visualized. BLI has the advantages of producing almost no unspecific background signals and no necessity for external excitation light. Hence, BLI is a highly sensitive and reliable detection method. Yet, the BLI reporter luciferase is not applicable with common microscopy techniques, therefore abolishing this method for cellular resolution imaging. FLI in turn, presents the appealing possibility to use one fluorescent reporter for whole body imaging as well as cellular resolution applying microscopy techniques. The absorption of light occurs mainly due to melanin and hemoglobin in wavelengths up to 650 nm. Therefore, the wavelength range beyond 650 nm may allow sensitive optical imaging even in deep tissues. For this reason, significant efforts are undertaken to isolate or develop genetically enhanced fluorescent proteins (FP) in this spectral range. “Katushka” also called FP635 has an emission close to this favorable spectrum and is reported as one of the brightest far-red FPs. Our experiments also clearly showed the superiority of BLI for whole body imaging over FLI. Based on these results we applied the superior BLI technique for the establishment of a pre-clinical multiple myeloma (MM) mouse model. MM is a B-cell disease, where malignant plasma cells clonally expand in the bone marrow (BM) of older people, causing significant morbidity and mortality. Chromosomal abnormalities, considered a hallmark of MM, are present in nearly all patients and may accumulate or change during disease progression. The diagnosis of MM is based on clinical symptoms, including the CRAB criteria: increased serum calcium levels, renal insufficiency, anemia, and bone lesions (osteolytic lesions or osteoporosis with compression fractures). Other clinical symptoms include hyperviscosity, amyloidosis, and recurrent bacterial infections. Additionally, patients commonly exhibit more than 30% clonal BM plasma cells and the presence of monoclonal protein is detected in serum and/or urine. With current standard therapies, MM remains incurable and patients diagnosed with MM between 2001 and 2007 had a 5-year relative survival rate of only 41%. Therefore, the development of new drugs or immune cell-based therapies is desirable and necessary. To this end we developed the MOPC-315 cell line based syngeneic MM mouse model. MOPC-315 cells were labeled with luciferase for in vivo detection by BLI. We validated the non-invasively obtained BLI data with histopathology, measurement of idiotype IgA serum levels and flow cytometry. All methods affirmed the reliability of the in vivo BLI data for this model. We found that this orthotopic MM model reflects several key features of the human disease. MOPC-315 cells homed efficiently to the BM compartment including subsequent proliferation. Additionally, cells disseminated to distant skeletal parts, leading to the typical multifocal MM growth. Osteolytic lesions and bone remodeling was also detected. We found evidence that the cell line had retained plasticity seen by dynamic receptor expression regulation in different compartments such as the BM and the spleen.
The capacity to develop immunological memory is a hallmark of the adaptive immune system. To investigate the role of Samd3 for cellular immune responses and memory development, we generated a conditional knock-out mouse including a fluorescent reporter and a huDTR cassette for conditional depletion of Samd3-expressing cells. Samd3 expression was observed in NK cells and CD8 T cells, which are known for their specific function against intracellular pathogens like viruses. After acute viral infections, Samd3 expression was enriched within memory precursor cells and the frequency of Samd3-expressing cells increased during the progression into the memory phase. Similarly, during chronic viral infections, Samd3 expression was predominantly detected within precursors of exhausted CD8 T cells that are critical for viral control. At the functional level however, Samd3-deficient CD8 T cells were not compromised in the context of acute infection with Vaccinia virus or chronic infection with Lymphocytic choriomeningitis virus. Taken together, we describe a novel multifunctional mouse model to study the role of Samd3 and Samd3-expressing cells. We found that Samd3 is specifically expressed in NK cells, memory CD8 T cells, and precursor exhausted T cells during viral infections, while the molecular function of this enigmatic gene remains further unresolved.
Farnesol, produced by the polymorphic fungus Candida albicans, is the first quorum-sensing molecule discovered in eukaryotes. Its main function is control of C. albicans filamentation, a process closely linked to pathogenesis. In this study, we analyzed the effects of farnesol on innate immune cells known to be important for fungal clearance and protective immunity. Farnesol enhanced the expression of activation markers on monocytes (CD86 and HLA-DR) and neutrophils (CD66b and CD11b) and promoted oxidative burst and the release of proinflammatory cytokines (tumor necrosis factor alpha [TNF-\(\alpha\)] and macrophage inflammatory protein 1 alpha [MIP-1 \(\alpha\)]). However, this activation did not result in enhanced fungal uptake or killing. Furthermore, the differentiation of monocytes to immature dendritic cells (iDC) was significantly affected by farnesol. Several markers important for maturation and antigen presentation like CD1a, CD83, CD86, and CD80 were significantly reduced in the presence of farnesol. Furthermore, farnesol modulated migrational behavior and cytokine release and impaired the ability of DC to induce T cell proliferation. Of major importance was the absence of interleukin 12 (IL-12) induction in iDC generated in the presence of farnesol. Transcriptome analyses revealed a farnesol-induced shift in effector molecule expression and a down-regulation of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor during monocytes to iDC differentiation. Taken together, our data unveil the ability of farnesol to act as a virulence factor of C. albicans by influencing innate immune cells to promote inflammation and mitigating the Th1 response, which is essential for fungal clearance.
Best disease (OMIM 153700) is an early-onset, autosomal dominant maculopathy characterized by egg yolk-like lesions in the central retina. The disease gene, the vitelliform macular dystrophy gene type 2 (VMD2), encodes a 585-aa VMD2 transmembrane protein, termed bestrophin. The protein is predominantly expressed on the basolateral side of the retinal pigment epithelium (RPE) and is thought to be involved in the transport of chloride ions. Bestrophin as well as three closely related VMD2-like proteins (VMD2L1-L3) contain multiple putative transmembrane (TM) domains and an invariant tripeptide (RFP) motif in the N-terminal half of the protein. This and the tissue-restricted expression to polarized epithelial cells are typical features of the VMD2 RFP-TM family. Best disease is predominantly caused by missense mutations, clustering in four distinct „hotspots“ in the evolutionary highly conserved N-terminal region of the protein. To further augment the spectrum of mutations and to gain novel insights into the underlying molecular mechanisms, we screened VMD2 in a large cohort of affected patients. In total, nine novel VMD2 mutations were identified, raising the total number of known Best disease-related mutations from 83 to 92. Eight out of nine novel mutations are hotspot-specific missense mutations, underscoring their functional/structural significance and corroborating the dominant-negative nature of the mutations. Of special interest is a one-basepair deletion (Pro260fsX288) encoding a truncated protein with a deletion of an important functional domain (TM domain four) as well as the entire C-terminal half of bestrophin. For the first time, a nonsense mutation leading to a 50 % non-functional protein has been identified suggesting that on rare occassions Best disease may be caused by haploinsufficiency. Molecular diagnostics strongly requires a reliable classification of VMD2 sequence changes into pathogenic and non-pathogenic types. Since the molecular pathomechanism is unclear at present, the pathogenicity of novel sequence changes of VMD2 are currently assessed in light of known mutations. We therefore initiated a publicly accessible VMD2 mutation database (http://www.uni-wuerzburg.de/humangenetics/vmd2.html) and are collecting and administrating the growing number of mutations, rare sequence variants and common polymorphisms. Missense mutations may disrupt the function of proteins in numerous ways. To evaluate the functional consequences of VMD2 mutations in respect to intracellular mislocalization and/or protein elimination, a set of molecular tools were generated. These included the establishment of an in vitro COS7 heterologous expression assay, the generation of numerous VMD2 mutations by site-directed mutagenesis as well as the development of bestrophin-specific antibodies. Surprisingly, membrane fractionation/Western blot experiments revealed no significant quantitative differences between intact and mutant bestrophin. Irrelevant of the type or location of mutation, incorporation of mutant bestrophin to the membraneous fraction was observed. Thus, impaired membrane integration may be ruled out as causative pathomechanism of Best disease consistent with a dominant-negative effect of the mutations. In a different approach, efforts were directed towards identifying and characterizing the VMD2 RFP-TM protein family in mouse. While clarification of the genomic organization of murine Vmd2 was required as basis to generate Vmd2-targeted animals (see below), the study of closely related proteins (Vmd2L1, Vmd2L2 and Vmd2L3) may provide further clues as to the function of bestrophin. For this, biocomputational as well as RT PCR analyses were performed. Moreover, the novel genes were analyzed by real time quantitative RT PCR, displaying predominant expression in testis, colon and skeletal muscle of Vmd2, Vmd2L1 and Vmd2L3 transcripts, respectively as well as in eye tissue. Interestingly, neither an ORF was determined for murine Vmd2L2 nor was the transcript present in a panel of 12 mouse tissues, suggesting that murine Vmd2L2 may represent a functionally inactive pseudogene. The murine Vmd2L3 gene, as its human counterpart, is a highly differentially spliced transcript. Finally, generating mouse models of Best disease will provide essential tools to investigate the pathophysiology of bestrophin in vivo. We have initiated the generation of two different mouse lineages, one deficient of Vmd2 (knock-out) and the other carrying a human disease-related mutation (Tyr227Asn) in the orthologous murine gene (knock-in). Genetic engineering of both constructs has been achieved and presently, four ES clones harboring the homologous recombination event (Vmd2+/-) have been isolated and are ready for the subsequent steps to generate chimeric animals. The resulting mouse lineages will represent two key models to elucidate the functional role of bestrophin in Best disease, in RPE development and physiology.
Background
While hypercholesterolemia plays a causative role for the development of ischemic stroke in large vessels, its significance for cerebral small vessel disease (CSVD) remains unclear. We thus aimed to understand the detailed relationship between hypercholesterolemia and CSVD using the well described Ldlr\(^{−/-}\) mouse model.
Methods
We used Ldlr\(^{−/-}\) mice (n = 16) and wild-type (WT) mice (n = 15) at the age of 6 and 12 months. Ldlr\(^{−/-}\) mice develop high plasma cholesterol levels following a high fat diet. We analyzed cerebral capillaries and arterioles for intravascular erythrocyte accumulations, thrombotic vessel occlusions, blood-brain barrier (BBB) dysfunction and microbleeds.
Results
We found a significant increase in the number of erythrocyte stases in 6 months old Ldlr\(^{−/-}\) mice compared to all other groups (P < 0.05). Ldlr\(^{−/-}\) animals aged 12 months showed the highest number of thrombotic occlusions while in WT animals hardly any occlusions could be observed (P < 0.001). Compared to WT mice, Ldlr\(^{−/-}\) mice did not display significant gray matter BBB breakdown. Microhemorrhages were observed in one Ldlr\(^{−/-}\) mouse that was 6 months old. Results did not differ when considering subcortical and cortical regions.
Conclusions
In Ldlr\(^{−/-}\) mice, hypercholesterolemia is related to a thrombotic CSVD phenotype, which is different from hypertension-related CSVD that associates with a hemorrhagic CSVD phenotype. Our data demonstrate a relationship between hypercholesterolemia and the development of CSVD. Ldlr\(^{−/-}\) mice appear to be an adequate animal model for research into CSVD.
Alzheimer's disease (AD) is the most common form of dementia; however, mechanisms and biomarkers remain unclear. Here, we examined hippocampal CA4 and dentate gyrus subfields, which are less studied in the context of AD pathology, in post-mortem AD and control tissue to identify possible biomarkers. We performed mass spectrometry-based proteomic analysis combined with label-free quantification for identification of differentially expressed proteins. We identified 4,328 proteins, of which 113 showed more than 2-fold higher or lower expression in AD hippocampi than in control tissues. Five proteins were identified as putative AD biomarkers (MDH2, PCLO, TRRAP, YWHAZ, and MUC19 isoform 5) and were cross-validated by immunoblotting, selected reaction monitoring, and MALDI imaging. We also used a bioinformatics approach to examine upstream signalling interactions of the 113 regulated proteins. Five upstream signalling (IGF1, BDNF, ZAP70, MYC, and cyclosporin A) factors showed novel interactions in AD hippocampi. Taken together, these results demonstrate a novel platform that may provide new strategies for the early detection of AD and thus its diagnosis.
Background: Hereditary spastic paraplegias (HSPs) are characterised by lower limb spasticity due to degeneration of the corticospinal tract. We set out for an electrophysiological characterisation of motor and sensory tracts in patients with HSP.
Methods: We clinically and electrophysiologically examined a cohort of 128 patients with genetically confirmed or clinically probable HSP. Motor evoked potentials (MEPs) to arms and legs, somato-sensory evoked potentials of median and tibial nerves, and nerve conduction studies of tibial, ulnar, sural, and radial nerves were assessed.
Results: Whereas all patients showed clinical signs of spastic paraparesis, MEPs were normal in 27% of patients and revealed a broad spectrum with axonal or demyelinating features in the others. This heterogeneity can at least in part be explained by different underlying genotypes, hinting for distinct pathomechanisms in HSP subtypes. In the largest subgroup, SPG4, an axonal type of damage was evident. Comprehensive electrophysiological testing disclosed a more widespread affection of long fibre tracts involving peripheral nerves and the sensory system in 40%, respectively. Electrophysiological abnormalities correlated with the severity of clinical symptoms.
Conclusions: Whereas HSP is primarily considered as an upper motoneuron disorder, our data suggest a more widespread affection of motor and sensory tracts in the central and peripheral nervous system as a common finding in HSP. The distribution patterns of electrophysiological abnormalities were associated with distinct HSP genotypes and could reflect different underlying pathomechanisms. Electrophysiological measures are independent of symptomatic treatment and may therefore serve as a reliable biomarker in upcoming HSP trials.
The incidence of melanoma and nonmelanoma skin cancer has increased tremendously in recent years. Although novel treatment options have significantly improved patient outcomes, the prognosis for most patients with an advanced disease remains dismal. It is, thus, imperative to understand the molecular mechanisms involved in skin carcinogenesis in order to develop new targeted treatment strategies. Receptor tyrosine kinases (RTK) like the ERBB receptor family, including EGFR/ERBB1, ERBB2/NEU, ERBB3, and ERBB4, are important regulators of skin homeostasis and their dysregulation often results in cancer, which makes them attractive therapeutic targets. Members of the leucine‐rich repeats and immunoglobulin‐like domains protein family (LRIG1‐3) are ERBB regulators and thus potential therapeutic targets to manipulate ERBB receptors. Here, we analyzed the function of LRIG1 during chemically induced skin carcinogenesis in transgenic mice expressing LRIG1 in the skin under the control of the keratin 5 promoter (LRIG1‐TG mice). We observed a significant induction of melanocytic tumor formation in LRIG1‐TG mice and no difference in papilloma incidence between LRIG1‐TG and control mice. Our findings also revealed that LRIG1 affects ERBB signaling via decreased phosphorylation of EGFR and increased activation of the oncoprotein ERBB2 during skin carcinogenesis. The epidermal proliferation rate was significantly decreased during epidermal tumorigenesis under LRIG1 overexpression, and the apoptosis marker cleaved caspase 3 was significantly activated in the epidermis of transgenic LRIG1 mice. Additionally, we detected LRIG1 expression in human cutaneous squamous cell carcinoma and melanoma samples. Therefore, we depleted LRIG1 in human melanoma cells (A375) by CRISPR/Cas9 technology and found that this caused EGFR and ERBB3 downregulation in A375 LRIG1 knockout cells 6 h following stimulation with EGF. In conclusion, our study demonstrated that LRIG1‐TG mice develop melanocytic skin tumors during chemical skin carcinogenesis and a deletion of LRIG1 in human melanoma cells reduces EGFR and ERBB3 expression after EGF stimulation.
Sepsis caused by Neisseria meningitidis (meningococcus) is a rapidly progressing, life-threatening disease. Because its initial symptoms are rather unspecific, medical attention is often sought too late, i.e., when the systemic inflammatory response is already unleashed. This in turn limits the success of antibiotic treatment. The complement system is generally accepted as the most important innate immune determinant against invasive meningococcal disease since it protects the host through the bactericidal membrane attack complex. However, complement activation concomitantly liberates the C5a peptide, and it remains unclear whether this potent anaphylatoxin contributes to protection and/or drives the rapidly progressing immunopathogenesis associated with meningococcal disease. Here, we dissected the specific contribution of C5a receptor 1 (C5aR1), the canonical receptor for C5a, using a mouse model of meningococcal sepsis. Mice lacking C3 or C5 displayed susceptibility that was enhanced by >1,000-fold or 100-fold, respectively, consistent with the contribution of these components to protection. In clear contrast, C5ar1\(^{-/-}\) mice resisted invasive meningococcal infection and cleared N. meningitidis more rapidly than wild-type (WT) animals. This favorable outcome stemmed from an ameliorated inflammatory cytokine response to N. meningitidis in C5ar1\(^{-/-}\) mice in both in vivo and ex vivo whole-blood infections. In addition, inhibition of C5aR1 signaling without interference with the complement bactericidal activity reduced the inflammatory response also in human whole blood. Enticingly, pharmacologic C5aR1 blockade enhanced mouse survival and lowered meningococcal burden even when the treatment was administered after sepsis induction. Together, our findings demonstrate that C5aR1 drives the pathophysiology associated with meningococcal sepsis and provides a promising target for adjunctive therapy.
Importance:
The devastating consequences of N. meningitidis sepsis arise due to the rapidly arising and self-propagating inflammatory response that mobilizes antibacterial defenses but also drives the immunopathology associated with meningococcemia. The complement cascade provides innate broad-spectrum protection against infection by directly damaging the envelope of pathogenic microbes through the membrane attack complex and triggers an inflammatory response via the C5a peptide and its receptor C5aR1 aimed at mobilizing cellular effectors of immunity. Here, we consider the potential of separating the bactericidal activities of the complement cascade from its immune activating function to improve outcome of N. meningitidis sepsis. Our findings demonstrate that the specific genetic or pharmacological disruption of C5aR1 rapidly ameliorates disease by suppressing the pathogenic inflammatory response and, surprisingly, allows faster clearance of the bacterial infection. This outcome provides a clear demonstration of the therapeutic benefit of the use of C5aR1-specific inhibitors to improve the outcome of invasive meningococcal disease.
Lung cancer is the most common cancer worldwide and the leading cause of cancer-related deaths in both men and women. Despite the development of novel therapeutic interventions, the 5-year survival rate for non-small cell lung cancer (NSCLC) patients remains low, demonstrating the necessity for novel treatments. One strategy to improve translational research is the development of surrogate models reflecting somatic mutations identified in lung cancer patients as these impact treatment responses. With the advent of CRISPR-mediated genome editing, gene deletion as well as site-directed integration of point mutations enabled us to model human malignancies in more detail than ever before. Here, we report that by using CRISPR/Cas9-mediated targeting of Trp53 and KRas, we recapitulated the classic murine NSCLC model Trp53fl/fl:lsl-KRasG12D/wt. Developing tumors were indistinguishable from Trp53fl/fl:lsl-KRasG12D/wt-derived tumors with regard to morphology, marker expression, and transcriptional profiles. We demonstrate the applicability of CRISPR for tumor modeling in vivo and ameliorating the need to use conventional genetically engineered mouse models. Furthermore, tumor onset was not only achieved in constitutive Cas9 expression but also in wild-type animals via infection of lung epithelial cells with two discrete AAVs encoding different parts of the CRISPR machinery. While conventional mouse models require extensive husbandry to integrate new genetic features allowing for gene targeting, basic molecular methods suffice to inflict the desired genetic alterations in vivo. Utilizing the CRISPR toolbox, in vivo cancer research and modeling is rapidly evolving and enables researchers to swiftly develop new, clinically relevant surrogate models for translational research.
Juvenile neuronal ceroid lipofuscinosis (JNCL or Batten disease) caused by mutations in the CLN3 gene is the most prevalent inherited neurodegenerative disease in childhood resulting in widespread central nervous system dysfunction and premature death. The consequences of CLN3 mutation on the progression of the disease, on neuronal transmission, and on central nervous network dysfunction are poorly understood. We used Cln3 knockout (Cln3\(^{Δex1-6}\)) mice and found increased anxiety-related behavior and impaired aversive learning as well as markedly affected motor function including disordered coordination. Patch-clamp and loose-patch recordings revealed severely affected inhibitory and excitatory synaptic transmission in the amygdala, hippocampus, and cerebellar networks. Changes in presynaptic release properties may result from dysfunction of CLN3 protein. Furthermore, loss of calbindin, neuropeptide Y, parvalbumin, and GAD65-positive interneurons in central networks collectively support the hypothesis that degeneration of GABAergic interneurons may be the cause of supraspinal GABAergic disinhibition.
Loss of function mutations in the rsk2 gene cause Coffin-Lowry syndrome (CLS), which is associated with multiple symptoms including severe mental disabilities. Despite the characterization of ribosomal S6 kinase 2 (RSK2) as a protein kinase acting as a downstream effector of the well characterized ERK MAP-kinase signaling pathway, it turns out to be a challenging task to link RSK2 to specific neuronal processes dysregulated in case of mutation. Animal models such as mouse and Drosophila combine advanced genetic manipulation tools with in vivo imaging techniques, high-resolution connectome analysis and a variety of behavioral assays, thereby allowing for an in-depth analysis for gene functions in the nervous system. Although modeling mental disability in animal systems has limitations because of the complexity of phenotypes, the influence of genetic variation and species-specific characteristics at the neural circuit and behavioral level, some common aspects of RSK2 function in the nervous system have emerged, which will be presented. Only with this knowledge our understanding of the pathophysiology of CLS can be improved, which might open the door for development of potential intervention strategies.
In the last decades, both the incidence and the severity of asthma have steadily increased. Furthermore, available therapies only treat the symptoms but do not cure the disease. Immune modulation induced by TLR agonists may be a promising novel approach to effectively treat asthma as it targets the underlying immunopathology directly rather than one mediator alone. The aim of this thesis was to investigate if the immunostimulatory properties of Toll-like receptor (TLR) agonists can be utilized to develop novel therapeutic intervention strategies for the treatment of asthma using murine models of allergic inflammation. For this purpose five different TLR agonists were tested in preclinical mouse models of acute and chronic asthma, both in preventive and therapeutic settings. Firstly, TLR-2, 3, 4, 7/8 and 9 agonists were delivered intratracheally at different doses before pulmonary allergen exposure in the asthma model of acute inflammation. TLR9 agonist CpG-containing oligodeoxynucleotides (CpG) > TLR7 agonist Resiquimod (R848) > TLR3 agonists poly(I:C) strongly reduced allergen induced airway eosinophilia and IL-4 levels in a dose-dependent manner. All TLR agonists increased neutrophil numbers, TLR4 agonist lipopolysaccharide (LPS) > TLR2 agonist lipoteichonic acid (LTA) > poly(I:C) > CpG > R848 and, with the exception of R848, the amount of pro-inflammatory cytokines in the airways. Suppressive effects were not dependent upon IFN-γ and IL-10 or associated with increased numbers of regulatory T cells in the airways. All TLR agonists, except LTA, similarly reduced airway eosinophilia and IL-4 levels when applied therapeutically after allergen challenge. These results show that the TLR agonists have different suppressive effects on TH2 responses in the airways which further depend on the dose and the experimental setup in which they were tested. Interestingly, all agonists induced airway neutrophilia, albeit to different degrees, raising the question if TLR ligands are safe for human use when applied directly into the lung. Different TLR agonists are also being developed for human use as adjuvants combined with allergen in specific immunotherapy. Recent clinical data suggest that this may be achieved by induction of allergen-specific TH1 responses. For this reason, the ability of different TLR agonists to induce allergen-specific TH1 and suppress allergen-specific TH2 responses in a preclinical setting was investigated in this thesis. Different doses of the TLR agonists were applied together with allergen, then mice were exposed to allergen aerosol. CpG > LPS >LTA dose-dependently strongly suppressed the development of airway eosinophilia with poly(I:C) and R848 having no effect. The decrease in eosinophilic numbers was associated withincreased neutrophils present in the airways. IL-4 and IL-5 levels in the bronchoalveolar lavage fluid were also decreased when poly(I:C), LPS, and CpG were used. All TLR agonists increased allergen-specific IgG2a, and with the exception of poly(I:C), reduced allergen-specific IgE levels in the serum. Cutaneous anaphylaxis to allergen was completely prevented when LPS or CpG were given as adjuvant. The strongest TH1 responses were induced by CpG and poly(I:C), characterized by the presence of IFN-γ in the bronchoalveolar lavage and the highest allergen-specific IgG2a levels in the serum. This data supports approaches to use TLR9 or TLR4 agonists for human therapy as adjuvant in combination with allergen in novel specific immunotherapy formulations. In the last part of the thesis, it was investigated if TLR activation can also affect the pathology of severe chronic asthma. Therapeutic administration of R848 or CpG reduced features of inflammation and remodeling. Both agonists showed superior effects to dexamethasone, with CpG being more efficient than R848. This result again supports a TLR9-based therapy as a viable option for the treatment of severe chronic asthma which may present a potential alternative for anti-inflammatory therapy with steroids. Taken together, the results of this thesis support the use of TLR agonists to treat asthma. The most favorable efficacy/safety ratio is to be expected from TLR-based therapies combining TLR4 or TLR9 agonists with allergen in specific immunotherapy. In regard to TLR agonist monotherapy, R848 and CpG showed the most promising profiles, CpG particularly in a model of severe chronic asthma. However, since all TLR agonists used in this study also showed pro-inflammatory potential, the safety aspect of such an approach needs to be taken into account.
The human-pathogenic bacterium Salmonella enterica adjusts and adapts to different environments while attempting colonization. In the course of infection nutrient availabilities change drastically. New techniques, "-omics" data and subsequent integration by systems biology improve our understanding of these changes. We review changes in metabolism focusing on amino acid and carbohydrate metabolism. Furthermore, the adaptation process is associated with the activation of genes of the Salmonella pathogenicity islands (SPIs). Anti-infective strategies have to take these insights into account and include metabolic and other strategies. Salmonella infections will remain a challenge for infection biology.
Acute graft-versus-host disease (aGvHD) is an immune syndrome associated with allogeneic hematopoietic cell transplantation (allo-HCT) that is mediated by alloreactive donor T cells attacking the gastrointestinal tract, liver, and skin of the host. Early diagnosis remains problematic and to date mainly relies on clinical symptoms and histopathology. Previously, different groups demonstrated that in order to cause aGvHD, alloreactive T cells require the expression of appropriate homing receptors to efficiently migrate from their priming sites to their target tissues. Therefore, the development of a predictive test based on the homing receptor expression profile of peripheral blood T cells seems attractive to identify patients at risk before the onset of aGvHD. The aim of this study was to analyze migrating alloreactive donor T cell kinetics in the peripheral blood early after allo-HCT in a murine model across minor histocompatibility antigens (miHAg) followed by a precise characterization of the homing receptor expression profile of migrating donor lymphocytes in order to identify suitable predictive markers. Combining daily bioluminescence imaging (BLI) and flow cytometry (FC) allowed defining two weeks of massive alloreactive donor T cell migration before clinical aGvHD symptoms became apparent. Peripheral blood donor T lymphocytes highly up-regulated the homing markers α4β7 integrin, and P- and E-selectin-ligand at peak time points of cell migration. The combination with the activation markers CD25 and CD69 and low expression levels of L-selectin allowed alloreactive donor T cell definition. Based on this migration phase we postulated a potential diagnostic window to precisely identify alloreactive donor T cells upon their homing receptor expression profile. Consequently, targeted pre-emptive treatment with rapamycin starting at the earliest detection time point of alloreactive donor T cells in the peripheral blood (day+6) significantly prolonged survival of treated mice. Based on this data, we propose a potential diagnostic window for alloreactive cell detection based on their homing receptor expression profile for a timely and effective therapeutic intervention before the clinical manifestation of aGvHD.