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The impact of the tissue context on tumor growth and drug response in medulloblastoma (MB) is poorly understood. To gain insights into the growth and dissemination behavior of the MB tumor cells under treatment, we combined three-dimensional cell culture screening with ex vivo organotypic cerebellum slice co-culture (OCSC), which allowed the assessment of tumor cell behavior in the tissue context.To identify druggable kinase pathways involved in invasion, we screened a panel of 274 kinase inhibitors and identified aurora kinase B (AURKB) as a potential anti-invasion drug target in MB. We validated tumor suppressive activities of the AURKB inhibitor (AURKBi) Barasertib (AZD1152-HQPA) and the structurally unrelated compound GSK-1070916 in cerebellum slice culture models for SHH, and Grp3 MB. Importantly, AURKBi are tumor suppressive in the tissue context, also in MB tumor cells that are in vitro resistant to the same treatment. We confirmed the requirement of AURKB for tumor growth and expansion in the tissue context through genetic suppression of AURKB by siRNA. We revealed that the combination of AURKBi with the SRC/BCR-ABL inhibitor Dasatinib acts synergistically to repress tumor growth and expansion in the highly invasive MB cell model ONS-76, but not in Grp3 MB cells. We demonstrate that tumor growth in the tissue context is suppressed by pharmacological inhibition of AURKB, comparable to the growth reduction observed after X-ray irradiation, which was used as the positive control. Finally, we show that exposure to µM concentrations of Barasertib does not cause developmental toxicity in fish larvae.In conclusion, we demonstrate that AURKB is essential for MB tumor growth and expansion in the tissue context and the inhibition of AURKB is equally efficient as irradiation in repressing tumor cell growth. In patients younger than three years, pharmacological targeting of AURKB may thus constitute a novel means to overcome radiotherapy limitations.

Abstract Background Inhibition of androgen receptor (AR) signaling is the main treatment strategy in advanced prostate cancer (PCa). A subset of castration resistant prostate cancer (CRPC) bypasses the AR blockade by increased fibroblast growth factor receptor (FGFR) signaling. The first‐ and second‐generation, non‐covalent FGFR inhibitors (FGFRis) have largely failed in the clinical trials against PCa. Purpose: In this study, we tested the drug sensitivity of LNCaP, VCaP, and CWR‐R1PCa cell lines to second‐generation, covalent FGFRis (FIIN1, FIIN2) and a novel FGFR downstream molecule inhibitor (FRS2αi). Methods 2D and 3D mono‐ and co‐cultures of cancer cells, and cancer‐associated fibroblasts (CAFs) were used to mimic tumor‐stroma interactions in the extracellular matrix (ECM). The treatment responses of the FGFR signaling molecules, the viability and proliferation of cancer cells, and CAFs were determined through immunoblotting, migration assay, cell viability assay, and real‐time imaging. Immunofluorescent and confocal microscopy images of control and treated cultures of cancer cells and CAFs, and their morphometric data were deduced. Results The FGFRis were more effective in mono‐cultures of the cancer cells compared with co‐cultures with CAFs. The FRS2αi was specifically effective in co‐cultures with CAFs but was not cytotoxic to CAF mono‐cultures as in the case of FIIN1 and FIIN2. At the molecular level, FRS2αi decreased p‐FRS2α, p‐ERK1/2, and activated apoptosis as monitored by cleaved caspase‐3 activity in a concentration‐dependent manner in the co‐cultures. We observed no synergistic drug efficacy in the combination treatment of the FGFRi with ARi, enzalutamide, and darolutamide. The FRS2αi treatment led to a decrease in proliferation of cancer cell clusters in co‐cultures as indicated by their reduced size and Ki67 expression. Conclusions CAFs exert a protective effect on cancer cells and should be included in the in vitro models to make them physiologically more relevant in screening and testing of FGFRis. The FRS2αi was the most potent agent in reducing the viability and proliferation of the 3D organotypic co‐cultures, mainly by disrupting the contact between CAFs and cancer cell clusters. The next‐generation FGFRi, FRS2αi, may be a better alternative treatment option for overcoming ARi treatment resistance in advanced PCa.

IntroductionThe potential for secondary use of health data to improve healthcare is currently not fully exploited. Health data is largely kept in isolated data silos and key infrastructure to aggregate these silos into standardized bodies of knowledge is underdeveloped. We describe the development, implementation, and evaluation of a federated infrastructure to facilitate versatile secondary use of health data based on Health Data Space nodes.Materials and methodsOur proposed nodes are self-contained units that digest data through an extract-transform-load framework that pseudonymizes and links data with privacy-preserving record linkage and harmonizes into a common data model (OMOP CDM). To support collaborative analyses a multi-level feature store is also implemented. A feasibility experiment was conducted to test the infrastructures potential for machine learning operations and deployment of other apps (e.g., visualization). Nodes can be operated in a network at different levels of sharing according to the level of trust within the network.ResultsIn a proof-of-concept study, a privacy-preserving registry for heart failure patients has been implemented as a real-world showcase for Health Data Space nodes at the highest trust level, linking multiple data sources including (a) electronical medical records from hospitals, (b) patient data from a telemonitoring system, and (c) data from Austria’s national register of deaths. The registry is deployed at the tirol kliniken, a hospital carrier in the Austrian state of Tyrol, and currently includes 5,004 patients, with over 2.9 million measurements, over 574,000 observations, more than 63,000 clinical free text notes, and in total over 5.2 million data points. Data curation and harmonization processes are executed semi-automatically at each individual node according to data sharing policies to ensure data sovereignty, scalability, and privacy. As a feasibility test, a natural language processing model for classification of clinical notes was deployed and tested.DiscussionThe presented Health Data Space node infrastructure has proven to be practicable in a real-world implementation in a live and productive registry for heart failure. The present work was inspired by the European Health Data Space initiative and its spirit to interconnect health data silos for versatile secondary use of health data.

Background: The recent rise of large language models has triggered renewed interest in medical free text data, which holds critical information about patients and diseases. However, medical free text is also highly sensitive. Therefore, de-identification is typically required but is complicated since medical free text is mostly unstructured. With the Masketeer algorithm, we present an effective tool to de-identify German medical text. Methods: We used an ensemble of different masking classes to remove references to identifiable data from over 35,000 clinical notes in accordance with the HIPAA Safe Harbor Guidelines. To retain additional context for readers, we implemented an entity recognition scheme and corpus-wide pseudonymization. Results: The algorithm performed with a sensitivity of 0.943 and specificity of 0.933. Further performance analyses showed linear runtime complexity (O(n)) with both increasing text length and corpus size. Conclusions: In the future, large language models will likely be able to de-identify medical free text more effectively and thoroughly than handcrafted rules. However, such gold-standard de-identification tools based on large language models are yet to emerge. In the current absence of such, we hope to provide best practices for a robust rule-based algorithm designed with expert domain knowledge.

Generative Deep Learning holds promise for mining the unexplored “chemical universe” for new drugs. Here, the authors demonstrate the de novo design of phosphoinositide 3-kinase gamma (PI3Kγ) inhibitors for the PI3K/Akt pathway in human tumor cells.

Analysis of the MAP4K4-STRN3 cooperation in medulloblastoma reveals its opposing regulation of Hippo activation and tissue invasion in cancer.

Die Digitalisierung verändert alle Lebensbereiche und damit auch die Anforderungen an zukünftige Ärztinnen und Ärzte. In einem gemeinsamen Ansatz haben interuniversitäre und interdisziplinäre Arbeitsgruppen der österreichischen öffentlichen medizinischen Universitäten und Fakultäten Ausbildungselemente zur Digitalisierung in der Medizin entwickelt. In einem ersten Schritt wurden diese Elemente als Wahlfächer implementiert, die nach einer Evaluierungsphase in die Curricula integriert werden. Zukünftige Ärzt:innen erhalten damit eine Basiskompetenz für den für Patient:innen nutzbringenden Einsatz digitaler Werkzeuge.

The finely tuned integration of intra- and extracellular cues by components of the mitogen-activated protein kinase (MAPK) signaling pathways controls the mutually exclusive phenotypic manifestations of uncontrolled growth and tumor cell dissemination. The Ser/Thr kinase MAP4K4 is an upstream integrator of extracellular cues involved in both proliferation and cell motility control. Initially identified as an activator of the c-Jun N-terminal kinase (JNK), the discovery of diverse functions and additional effectors of MAP4K4 beyond JNK signaling has considerably broadened our understanding of this complex kinase. The implication of MAP4K4 in the regulation of cytoskeleton dynamics and cell motility provided essential insights into its role as a pro-metastatic kinase in cancer. However, the more recently revealed role of MAP4K4 as an activator of the Hippo tumor suppressor pathway has complicated the understanding of MAP4K4 as an oncogenic driver kinase. To develop a better understanding of the diverse functions of MAP4K4 and their potential significance in oncogenesis and tumor progression, we have collected and assessed the current evidence of MAP4K4 implication in molecular mechanisms that control proliferation and promote cell motility. A better understanding of these mechanisms is particularly relevant in the brain, where MAP4K4 is highly expressed and under pathological conditions either drives neuronal cell death in neurodegenerative diseases or cell dissemination in malignant tumors. We review established effectors and present novel interactors of MAP4K4, which offer mechanistic insights into MAP4K4 function and may inspire novel intervention strategies. We discuss possible implications of novel interactors in tumor growth and dissemination and evaluate potential therapeutic strategies to selectively repress pro-oncogenic functions of MAP4K4.

Digitalisation is changing all areas of our daily life. This changing environment requires new competences from physicians in all specialities. This study systematically surveyed the knowledge, attitude, and interests of medical students. These results will help further develop the medical curriculum, as well as increase our understanding of future physicians by other healthcare market players. A web-based survey consisting of four sections was developed: Section one queried demographic data, section two assessed the current digital health knowledge of medical students, section three queried their attitudes about the future impact of digital health in medicine and section four assessed the recommendations medical students have for the medical curriculum in terms of digital health. This survey was distributed to all (11,978) student at all public Austrian medical schools. A total of 8.4% of the medical student population started the survey. At the knowledge self-assessment section, the medical students reached mean of 11.74 points (SD 4.42) out of a possible maximum of 32 (female mean 10.66/ SD 3.87, male mean 13.34/SD 4.50). The attitude section showed that students see digitalisation as a threat, especially with respect to the patient–physician relationship. The curriculum recommendation section showed a high interest for topics related to AI, a per study year increasing interest in impact of digital health in communication, as well as a decreasing interest in robotic related topics. The attitude towards digital health can be described as sceptical. To ensure that future physicians keep pace with this development and fulfil their responsibility towards the society, medical schools need to be more proactive to foster the understanding of medical students that digital health will persistently alter the medical practice.

Aberrantly activated kinase signaling pathways drive invasion and dissemination in medulloblastoma (MB). A majority of tumor-promoting kinase signaling pathways feed into the mitogen-activated protein kinase (MAPK) extracellular regulated kinase (ERK1/2) pathway. The activation status of ERK1/2 during invasion of MB cells is not known and its implication in invasion control unclear.We established a synthetic kinase activation relocation sensor (SKARS) for the MAPK ERK1/2 pathway in MB cells for real-time measuring of drug response. We used 3D invasion assays and organotypic cerebellum slice culture to test drug effects in a physiologically relevant tissue environment.We found that hepatocyte growth factor (HGF), epidermal growth factor (EGF), or basic fibroblast growth factor (bFGF) caused rapid nuclear ERK1/2 activation in MB cells, which persisted for several hours. Concomitant treatment with the BCR/ABL kinase inhibitor dasatinib completely repressed nuclear ERK1/2 activity induced by HGF and EGF but not by bFGF. Increased nuclear ERK1/2 activity correlated positively with speed of invasion. Dasatinib blocked ERK-associated invasion in the majority of cells, but we also observed fast-invading cells with low ERK1/2 activity. These ERK1/2-low, fast-moving cells displayed a rounded morphology, while ERK-high fast-moving cells displayed a mesenchymal morphology. Dasatinib effectively blocked EGF-induced proliferation while it only moderately repressed tissue invasion, indicating that a subset of cells may evade invasion repression by dasatinib through non-mesenchymal motility. Thus, growth factor-induced nuclear activation of ERK1/2 is associated with mesenchymal motility and proliferation in MB cells and can be blocked with the BCR/ABL kinase inhibitor dasatinib.

Abstract Next-generation sequencing platforms are routinely used for molecular assignment due to their high impact for risk stratification and prognosis in medulloblastomas. Yet, low and middle-income countries still lack an accurate cost-effective platform to perform this allocation. TaqMan Low Density array (TLDA) assay was performed using a set of 20 genes in 92 medulloblastoma samples. The same methodology was assessed in silico using microarray data for 763 medulloblastoma samples from the GSE85217 study, which performed MB classification by a robust integrative method (Transcriptional, Methylation and cytogenetic profile). Furthermore, we validated in 11 MBs samples our proposed method by Methylation Array 450 K to assess methylation profile along with 390 MB samples (GSE109381) and copy number variations. TLDA with only 20 genes accurately assigned MB samples into WNT, SHH, Group 3 and Group 4 using Pearson distance with the average-linkage algorithm and showed concordance with molecular assignment provided by Methylation Array 450 k. Similarly, we tested this simplified set of gene signatures in 763 MB samples and we were able to recapitulate molecular assignment with an accuracy of 99.1% (SHH), 94.29% (WNT), 92.36% (Group 3) and 95.40% (Group 4), against 97.31, 97.14, 88.89 and 97.24% (respectively) with the Ward.D2 algorithm. t-SNE analysis revealed a high level of concordance (k = 4) with minor overlapping features between Group 3 and Group 4. Finally, we condensed the number of genes to 6 without significantly losing accuracy in classifying samples into SHH, WNT and non-SHH/non-WNT subgroups. Additionally, we found a relatively high frequency of WNT subgroup in our cohort, which requires further epidemiological studies. TLDA is a rapid, simple and cost-effective assay for classifying MB in low/middle income countries. A simplified method using six genes and restricting the final stratification into SHH, WNT and non-SHH/non-WNT appears to be a very interesting approach for rapid clinical decision-making.

Abstract Medulloblastoma (MB) is a paediatric cancer of the cerebellum that can develop cerebellar and leptomeningeal metastases. Local brain tissue infiltration, the underlying cause of metastasis and relapse, remains unexplored. We developed a novel approach to investigate tissue infiltration of MB using organotypic cerebellum slice culture (OCSC). We show that cellular and structural components of cerebellar tissue in OCSCs are maintained for up to 30 days ex vivo, and that OCSCs foster tumour growth and cell proliferation. Using cell-based models of sonic hedgehog (SHH) and group 3 (G3) MB, we quantified tumour growth and infiltration and determined the morphological characteristics of the infiltrating cells. We observed basal levels of dissemination occurring in both subgroups with cells migrating either individually or collectively as clusters. Collective cerebellar tissue infiltration of SHH MB cells was further enhanced by EGF but not HGF, demonstrating differential tumour cell responses to microenvironmental cues. We found G3 cells to be hyper proliferative and observed aggressive tumour expansion even in the absence of exogenous growth factors. Our study thus provides unprecedented insights into brain tissue infiltration of SHH and G3 MB cells and reveals the cellular basis of the tumour progressing functions of EGF in SHH MB.

Summary: The microenvironment shapes cell behavior and determines metastatic outcomes of tumors. We addressed how microenvironmental cues control tumor cell invasion in pediatric medulloblastoma (MB). We show that bFGF promotes MB tumor cell invasion through FGF receptor (FGFR) in vitro and that blockade of FGFR represses brain tissue infiltration in vivo. TGF-β regulates pro-migratory bFGF function in a context-dependent manner. Under low bFGF, the non-canonical TGF-β pathway causes ROCK activation and cortical translocation of ERK1/2, which antagonizes FGFR signaling by inactivating FGFR substrate 2 (FRS2), and promotes a contractile, non-motile phenotype. Under high bFGF, negative-feedback regulation of FRS2 by bFGF-induced ERK1/2 causes repression of the FGFR pathway. Under these conditions, TGF-β counters inactivation of FRS2 and restores pro-migratory signaling. These findings pinpoint coincidence detection of bFGF and TGF-β signaling by FRS2 as a mechanism that controls tumor cell invasion. Thus, targeting FRS2 represents an emerging strategy to abrogate aberrant FGFR signaling. : Santhana Kumar et al. describe how growth factors in the microenvironment of medulloblastoma, the most common malignant brain tumor in children, are sensed by the tumor cells and how they respond to these factors. They identify the adaptor protein FRS2 as a key molecule controlling growth factor-induced tissue infiltration. Keywords: medulloblastoma, migration, invasion, FGFR1 signaling, FRS2, bFGF, TGF-β signaling, tumor microenvironment, organotypic cerebellum slice culture

Embryonal tumors of the nervous system are the leading cause of childhood cancer-related morbidity and mortality. Medulloblastoma, supratentorial primitive neuroectodermal tumors, atypical teratoid/rhabdoid tumor and neuroblastoma account for more than 20% of childhood malignancies and typify the current neural embryonal tumor model in pediatric oncology. Mechanisms driving the formation of these tumors point towards impaired differentiation of neuronal and neuron-associated cells during the development of the nervous system as an important factor. The importance of microRNAs (miRNAs) for proper embryonic cell function has been confirmed and their aberrant expressions have been linked to tumor development. The role of miRNAs in controlling essential regulators of key pathways implicated in tumor development makes their use in diagnostics a powerful tool to be used for early detection of cancer, risk assessment and prognosis, as well as for the design of innovative therapeutic strategies. In this review we focus on the significance of miRNAs involved in the biology of embryonal neural tumors, delineate their clinical significance and discuss their potential as a novel therapeutic target.

Cell dissemination from an initial site of growth is a highly coordinated and controlled process that depends on cell motility. The mechanistic principles that orchestrate cell motility, namely cell shape control, traction and force generation, are highly conserved between cells of different origins. Correspondingly, the molecular mechanisms that regulate these critical aspects of migrating cells are likely functionally conserved too. Thus, cell motility deregulation of unrelated pathogenesis could be caused and maintained by similar mechanistic principles. One such motility deregulation disorder is the leukoproliferative cattle disease Tropical Theileriosis, which is caused by the intracellular, protozoan parasite Theileria annulata. T. annulata transforms its host cell and promotes the dissemination of parasite-infected cells throughout the body of the host. An analogous condition with a fundamentally different pathogenesis is metastatic cancer, where oncogenically transformed cells disseminate from the primary tumor to form distant metastases. Common to both diseases is the dissemination of motile cells from the original site. However, unlike metastatic cancer, host cell transformation by Theileria parasites can be reverted by drug treatment and cell signaling be analyzed under transformed and non-transformed conditions. We have used this reversible transformation model and investigated parasite control of host cell motile properties in the context of inflammatory signaling in Ma M. et al. [PLoS Pathog (2014) 10: e1004003]. We found that parasite infection promotes the production of the inflammatory cytokine TNFα in the host macrophage. We demonstrated that increased TNFα triggers motile and invasive properties by enhancing actin cytoskeleton remodeling and cell motility through the ser/thr kinase MAP4K4. We concluded that inflammatory conditions resulting in increased TNFα could facilitate cell dissemination by activating the actin cytoskeleton regulatory kinase MAP4K4. We discuss here the relevance of TNFα-MAP4K4 signaling for pathogen-driven cell dissemination and its potential impact on the induction of metastasis in human cancer.

Embryonal tumors include a heterogeneous group of highly malignant neoplasms that primarily affect infants and children and are characterized by a high rate of mortality and treatment-related morbidity, hence improved therapies are clearly needed. G-quadruplexes are special secondary structures adopted in guanine (G)-rich DNA sequences that are often present in biologically important regions, e.g. at the end of telomeres and in the regulatory regions of oncogenes such as MYC. Owing to the significant roles that both telomeres and MYC play in cancer cell biology, G-quadruplexes have been viewed as emerging therapeutic targets in oncology and as tools for novel anticancer drug design. Several compounds that target these structures have shown promising anticancer activity in tumor xenograft models and some of them have entered Phase II clinical trials. In this review we examine approaches to DNA targeted cancer therapy, summarize the recent developments of G-quadruplex ligands as anticancer drugs and speculate on the future direction of such structures as a potential novel therapeutic strategy for embryonal tumors of the nervous system.

The intracellular, protozoan Theileria species parasites are the only eukaryotes known to transform another eukaryotic cell. One consequence of this parasite-dependent transformation is the acquisition of motile and invasive properties of parasitized cells in vitro and their metastatic dissemination in the animal, which causes East Coast Fever (T. parva) or Tropical Theileriosis (T. annulata). These motile and invasive properties of infected host cells are enabled by parasite-dependent, poorly understood F-actin dynamics that control host cell membrane protrusions. Herein, we dissected functional and structural alterations that cause acquired motility and invasiveness of T. annulata-infected cells, to understand the molecular basis driving cell dissemination in Tropical Theileriosis. We found that chronic induction of TNFα by the parasite contributes to motility and invasiveness of parasitized host cells. We show that TNFα does so by specifically targeting expression and function of the host proto-oncogenic ser/thr kinase MAP4K4. Blocking either TNFα secretion or MAP4K4 expression dampens the formation of polar, F-actin-rich invasion structures and impairs cell motility in 3D. We identified the F-actin binding ERM family proteins as MAP4K4 downstream effectors in this process because TNFα-induced ERM activation and cell invasiveness are sensitive to MAP4K4 depletion. MAP4K4 expression in infected cells is induced by TNFα-JNK signalling and maintained by the inhibition of translational repression, whereby both effects are parasite dependent. Thus, parasite-induced TNFα promotes invasive motility of infected cells through the activation of MAP4K4, an evolutionary conserved kinase that controls cytoskeleton dynamics and cell motility. Hence, MAP4K4 couples inflammatory signaling to morphodynamic processes and cell motility, a process exploited by the intracellular Theileria parasite to increase its host cell's dissemination capabilities.

Recent technical advances have broadened our understanding of processes that govern mammalian cell migration in health and disease but many of the molecular and morphological alterations that precede and accompany movement of cells - in particular in three-dimensional (3D) environments - are still incompletely understood. In this manuscript, using high-resolution and time-lapse microscopy imaging approaches, we describe morphodynamic processes during rounded/amoeboid cell invasion and molecules associated with the cellular invasion structures. We used macrophages infected with the intracellular protozoan parasite Theileria annulata, which causes Tropical Theileriosis in susceptible ruminants such as domestic cattle. T. annulata transforms its host cell that, as a result, acquires many characteristics of human cancer cells including a markedly increased potential to migrate, disseminate and expand in the body of the host animal. Hence, virulence of the disease is associated with the capability of infected cells to disseminate inside the host. Using T. annulata-transformed macrophages as a model system, we described a novel mode of rounded/amoeboid macrophage migration. We show that filopodia-like membrane extensions at the leading edge lead the way and further evolve in blebbing membrane protrusions to promote progressive expansion of the matrix. Associated with focal invasion structures we detected ezrin, radixin, moesin-family proteins and their regulatory kinase MAP4K4. Furthermore, we linked Rho-kinase activity to contractile force generation, which is essential for infected cell motility. Thus, the motility mode of these parasite-transformed macrophages contrasts with those described so far in human macrophages such as the tunneling or mesenchymal modes, which require engulfment, compaction and ingestion of matrix or proteolytic matrix degradation, respectively. Together, our data reveal protrusion dynamics at the leading edge of invading cells in 3D at unprecedented temporal and spatial resolution and suggest a novel mode of rounded/amoeboid invasive cell motility that exploits actin-driven filopodia formation in combination with pressure-driven membrane blebs.

Tyrolean Grey cattle represent a local breed with a population size of ∼5000 registered cows. In 2003, a previously unknown neurological disorder was recognized in Tyrolean Grey cattle. The clinical signs of the disorder are similar to those of bovine progressive degenerative myeloencephalopathy (weaver syndrome) in Brown Swiss cattle but occur much earlier in life. The neuropathological investigation of an affected calf showed axonal degeneration in the central nervous system (CNS) and femoral nerve. The pedigrees of the affected calves suggested a monogenic autosomal recessive inheritance. We localized the responsible mutation to a 1.9 Mb interval on chromosome 16 by genome-wide association and haplotype mapping. The MFN2 gene located in this interval encodes mitofusin 2, a mitochondrial membrane protein. A heritable human axonal neuropathy, Charcot-Marie-Tooth disease-2A2 (CMT2A2), is caused by MFN2 mutations. Therefore, we considered MFN2 a positional and functional candidate gene and performed mutation analysis in affected and control Tyrolean Grey cattle. We did not find any non-synonymous variants. However, we identified a perfectly associated silent SNP in the coding region of exon 20 of the MFN2 gene. This SNP is located within a putative exonic splice enhancer (ESE) and the variant allele leads to partial retention of the entire intron 19 and a premature stop codon in the aberrant MFN2 transcript. Thus we have identified a highly unusual splicing defect, where an exonic single base exchange leads to the retention of the preceding intron. This splicing defect represents a potential explanation for the observed degenerative axonopathy. Marker assisted selection can now be used to eliminate degenerative axonopathy from Tyrolean Grey cattle.

Theileria parasites invade and transform bovine leukocytes causing either East Coast fever (T. parva), or tropical theileriosis (T. annulata). Susceptible animals usually die within weeks of infection, but indigenous infected cattle show markedly reduced pathology, suggesting that host genetic factors may cause disease susceptibility. Attenuated live vaccines are widely used to control tropical theileriosis and attenuation is associated with reduced invasiveness of infected macrophages in vitro. Disease pathogenesis is therefore linked to aggressive invasiveness, rather than uncontrolled proliferation of Theileria-infected leukocytes. We show that the invasive potential of Theileria-transformed leukocytes involves TGF-b signalling. Attenuated live vaccine lines express reduced TGF-b2 and their invasiveness can be rescued with exogenous TGF-b. Importantly, infected macrophages from disease susceptible Holstein-Friesian (HF) cows express more TGF-b2 and traverse Matrigel with great efficiency compared to those from disease-resistant Sahiwal cattle. Thus, TGF-b2 levels correlate with disease susceptibility. Using fluorescence and time-lapse video microscopy we show that Theileria-infected, disease-susceptible HF macrophages exhibit increased actin dynamics in their lamellipodia and podosomal adhesion structures and develop more membrane blebs. TGF-b2-associated invasiveness in HF macrophages has a transcription-independent element that relies on cytoskeleton remodelling via activation of Rho kinase (ROCK). We propose that a TGF-b autocrine loop confers an amoeboid-like motility on Theileria-infected leukocytes, which combines with MMP-dependent motility to drive invasiveness and virulence.