Biology subjects

Orth, M.

Publications and source records attributed to Orth, M..

9 recordsLinked to original sources

bioRxiv2026

Whole genome-based Characterization of Virulence and Antimicrobial Resistance Determinants in Clinical Campylobacter jejuni Isolates from Minnesota, 2018-2021

Campylobacter jejuni is a leading cause of foodborne gastroenteritis globally and is classified by the CDC as a serious public health threat due to increasing resistance to fluoroquinolones and macrolides. This study used whole-genome sequencing to characterize the virulence and antimicrobial resistance profiles of 2,783 clinical C. jejuni isolates collected from Minnesota residents from 2018 through 2021. More than 90% of the isolates had genes related to stress defense (rpoN and htrB), cytolethal distending toxin (cdtA, cdtB, and cdtC), and cell adhesion and invasion (ciaB, cadF, and flaC). A diverse array of antimicrobial resistance genes was detected, with beta-lactam resistance genes having a particularly high prevalence. The gyrA point mutation associated with quinolone resistance was present in 29% of isolates. To evaluate the correlation between genotypic and phenotypic antimicrobial resistance profiles, the antimicrobial susceptibility testing results from a subset of isolates were compared with genotypic resistance profiles. Results showed a strong overall correlation, particularly for tetracycline and quinolones, though 24 discrepancies were detected. In the majority of discrepancies (n=21), genomic antimicrobial resistance markers were absent in isolates that were phenotypically resistant, suggesting possible unknown resistance mechanisms or limitations in current sequencing methods. The remaining three discrepancies occurred in isolates that had the tet(O) resistance gene but were susceptible to tetracycline phenotypically. These findings highlight the value of whole genome sequencing in improving antimicrobial resistance surveillance and understanding virulence factors in C. jejuni, supporting its integration into routine monitoring practices to better manage and understand antimicrobial resistance in foodborne pathogens.

microbiology↗

bioRxiv2024

Genetic modifiers of somatic expansion and clinical phenotypes in Huntington's disease reveal shared and tissue-specific effects

Huntingtons disease (HD), due to expansion of a CAG repeat in HTT, is representative of a growing number of disorders involving somatically unstable short tandem repeats. We find that overlapping and distinct genetic modifiers of clinical landmarks and somatic expansion in blood DNA reveal an underlying complexity and cell-type specificity to the mismatch repair-related processes that influence disease timing. Differential capture of non-DNA-repair gene modifiers by multiple measures of cognitive and motor dysfunction argues additionally for cell-type specificity of pathogenic processes. Beyond trans modifiers, differential effects are also illustrated at HTT by a 5-UTR variant that promotes somatic expansion in blood without influencing clinical HD, while, even after correcting for uninterrupted CAG length, a synonymous sequence change at the end of the CAG repeat dramatically hastens onset of motor signs without increasing somatic expansion. Our findings are directly relevant to therapeutic suppression of somatic expansion in HD and related disorders and provide a route to define the individual neuronal cell types that contribute to different HD clinical phenotypes.

genetics↗

bioRxiv2022

Abnormal molecular signatures of inflammation, energy metabolism and vesicle biology in human Huntington disease peripheral tissues

BackgroundA major challenge in neurodegenerative diseases concerns identifying biological disease signatures that track with disease progression or respond to an intervention. Several clinical trials in Huntington disease (HD), an inherited, progressive neurodegenerative disease, are currently ongoing. Therefore, we examined whether peripheral tissues can serve as a source of readily accessible biological signatures at the RNA and protein level in HD patients. ResultsWe generated large, high-quality human datasets from skeletal muscle, skin and adipose tissue to probe molecular changes in human premanifest and early manifest HD patients - those most likely involved in clinical trials. In-depth single nucleotide polymorphism data across the HTT gene will facilitate the use of the generated primary- and iPSC cell lines in allele-specific targeting approaches. The analysis of the transcriptomics and proteomics data shows robust, stage-dependent dysregulation. Gene ontology analysis confirmed the involvement of inflammation and energy metabolism in peripheral HD pathogenesis. Furthermore, we observed changes in the homeostasis of extracellular vesicles, where we found consistent changes of genes and proteins involved in this process. ConclusionsOur omics data document the involvement of inflammation, energy metabolism and extracellular vesicle homeostasis. This demonstrates the potential to identify biological signatures from peripheral tissues in HD suitable as biomarkers in clinical trials. Together with the primary cell lines established from peripheral tissues and a large panel of iPSC lines that can serve as human models of HD, the generated data are a valuable and unique resource to advance the current understanding of molecular mechanisms driving HD pathogenesis.

neuroscience↗

bioRxiv2021

Nucleolar stress controls mutant Huntingtin toxicity and monitors Huntington disease progression

Transcriptional and cellular stress surveillance deficits are hallmarks of Huntingtons disease (HD), a fatal autosomal dominant neurodegenerative disorder, caused by a pathological expansion of CAG repeats in the Huntingtin (HTT) gene. The nucleolus, a dynamic nuclear biomolecular condensate and the site of ribosomal RNA (rRNA) transcription, is implicated in the cellular stress response and in protein quality control. While the exact pathomechanisms of HD remain unclear, the impact of nucleolar dysfunction on HD pathophysiology in vivo is elusive. Here we identified aberrant maturation of rRNA and decreased translational rate in association with human mutant Huntingtin (mHTT) expression. Genetic disruption of nucleolar integrity in vulnerable striatal neurons of the R6/2 HD mouse model decreases mHTT disperse state in the nucleus, exacerbating the motor deficits. The protein nucleophosmin 1 (NPM1), important for nucleolar integrity and rRNA maturation, loses its nucleolar localization. NPM1 de-localization occurs in the striatum and in the skeletal muscle of the progressive zQ175 knock-in HD mouse model, mimicking the phenotype of HD patients in skeletal muscle biopsies. Taken together, we showed that nucleolar integrity regulates the formation of mHTT inclusions in vivo, and identified NPM1 as a novel, readily detectable peripheral histopathological marker of HD progression.

neuroscience↗

bioRxiv2021

Heterogeneity in PHGDH protein expression potentiates cancer cell dissemination and metastasis

Cancer metastasis requires the transient activation of cellular programs enabling dissemination and seeding in distant organs. Genetic, transcriptional and translational intra-tumor heterogeneity contributes to this dynamic process. Beyond this, metabolic intra-tumor heterogeneity has also been observed, yet its role for cancer progression remains largely elusive. Here, we discovered that intra-tumor heterogeneity in phosphoglycerate dehydrogenase (PHGDH) protein expression drives breast cancer cell dissemination and metastasis formation. Specifically, we observed intra-tumor heterogeneous PHGDH expression in primary breast tumors, with low PHGDH expression being indicative of metastasis in patients. In mice, Phgdh protein, but not mRNA, expression is low in circulating tumor cells and early metastatic lesions, leading to increased dissemination and metastasis formation. Mechanistically, low PHGDH protein expression induces an imbalance in glycolysis that can activate sialic acid synthesis. Consequently, cancer cells undergo a partial EMT and show increased p38 as well as SRC phosphorylation, which activate cellular programs of dissemination. In turn, inhibition of sialic acid synthesis through knock-out of cytidine monophosphate N-acetylneuraminic acid synthetase (CMAS) counteracts the increased cancer cell dissemination and metastasis induced by low PHGDH expression. In conclusion, we find that heterogeneity in PHGDH protein expression promotes cancer cell dissemination and metastasis formation.

cancer biology↗

bioRxiv2020

The onset and prevalence of motor and psychiatric symptoms in Huntingtons disease

ObjectiveTo assess the prevalence, timing and functional impact of psychiatric, cognitive and motor abnormalities in Huntingtons disease (HD) gene carriers, we analysed retrospective clinical data from individuals with manifest HD. MethodsClinical features of HD patients were analysed for 6316 individuals in the European REGISTRY study from 161 sites across 17 countries. Data came from clinical history and the patient-completed Clinical Characteristics Questionnaire that assessed eight symptoms: motor, cognitive, apathy, depression, perseverative/obsessive behavior, irritability, violent/aggressive behavior, and psychosis. Multiple logistic regression was used to analyse relationships between symptoms and functional outcomes. ResultsThe initial manifestation of HD is increasingly likely to be motor, and less likely to be psychiatric, as age at presentation increases, and is independent of pathogenic CAG repeat length. The Clinical Characteristics Questionnaire captures data on non-motor symptom prevalence that correlate specifically with validated clinical measures. Psychiatric and cognitive symptoms are common in HD gene carriers, with earlier onsets associated with longer CAG repeats. 42.4% of HD patients reported at least one psychiatric or cognitive symptom before motor symptoms, with depression most common. Each non-motor symptom was associated with significantly reduced total functional capacity scores. ConclusionsPsychiatric and cognitive symptoms are common and functionally debilitating in HD gene carriers. They require recognition and targeting with clinical outcome measures and treatments. However, as it is impossible to distinguish confidently between non-motor symptoms arising from HD and primary psychiatric disorders, particularly in younger pre-manifest patients, non-motor symptoms should not be used to make a clinical diagnosis of HD.

neuroscience↗

bioRxiv2019

Genetic overlap between psychiatric disorders and neuropsychiatric symptoms in HD

Huntingtons disease (HD) is an inherited neurodegenerative disorder caused by an expanded CAG repeat in the HTT gene. It is diagnosed following a standardized exam of motor control and often presents with cognitive decline and psychiatric symptoms. Recent studies have detected genetic loci modifying the age at onset of motor symptoms in HD, but genetic factors influencing cognitive and psychiatric presentations are unknown. We tested the hypothesis that psychiatric and cognitive symptoms in HD are influenced by the same common genetic variation as in the general population by constructing polygenic risk scores from large genome-wide association studies of psychiatric and neurodegenerative disorders, and of intelligence, and testing for correlation with the presence of psychiatric and cognitive symptoms in a large sample (n=5160) of HD patients. Polygenic risk score for major depression was associated specifically with increased risk of depression in HD, as was schizophrenia risk score with psychosis and irritability. Cognitive impairment and apathy were associated with reduced polygenic risk score for intelligence. In general, polygenic risk scores for psychiatric disorders, particularly depression and schizophrenia, are associated with increased risk of the corresponding psychiatric symptoms in HD, suggesting a common genetic liability. However, the genetic liability to cognitive impairment and apathy appears to be distinct from other psychiatric symptoms in HD. No associations were observed between HD symptoms and risk scores for other neurodegenerative disorders. These data provide a rationale for treatments effective in depression and schizophrenia to be used to treat depression and psychotic symptoms in HD.

genetics↗

bioRxiv2019

Huntington's disease onset is determined by length of uninterrupted CAG, not encoded polyglutamine, and is modified by DNA maintenance mechanisms

The effects of variable, glutamine-encoding, CAA interruptions indicate that a property of the uninterrupted HTT CAG repeat sequence, distinct from huntingtins polyglutamine segment, dictates the rate at which HD develops. The timing of onset shows no significant association with HTT cis-eQTLs but is influenced, sometimes in a sex-specific manner, by polymorphic variation at multiple DNA maintenance genes, suggesting that the special onset-determining property of the uninterrupted CAG repeat is a propensity for length instability that leads to its somatic expansion. Additional naturally-occurring genetic modifier loci, defined by GWAS, may influence HD pathogenesis through other mechanisms. These findings have profound implications for the pathogenesis of HD and other repeat diseases and question a fundamental premise of the "polyglutamine disorders".

genetics↗

bioRxiv2018

Fndc3a (Fibronectin Domain Containing Protein 3A) influences median fin fold development and caudal fin regeneration in zebrafish by ECM alteration.

Summary statementWe investigated potential functions of Fndc3a during caudal fin development and regeneration in zebrafish. Reduced function interferes with correct epidermal cells structure and implies a role during vertebrate extremity development.\n\nAbstractInherited genetic alterations are often found to be disease-causing factors of patient phenotypes. To unravel the molecular consequences of newly identified factors functional investigations in vivo are eminent. We investigated molecular functions of FNDC3A (Fibronectin Domain Containing Protein 3A; HUGO), a novel candidate gene for split-hand/foot malformations (SHFM) in humans, by utilizing zebrafish (Danio rerio) as a vertebrate model. Patients with congenital SHFM display prominent limb malformations, which are caused by disturbance of limb development due to defects in apical ectodermal ridge (AER) establishment and maintenance. Initial gene expression and protein localization studies clarified the presence of fndc3a in developing and regenerating fins of zebrafish. For functional studies we established a hypomorphic fndc3a mutant line (fndc3awue1/wue1) via CRISPR/Cas9, exhibiting phenotypic malformations and changed gene expression patterns during early stages of median fin fold development. Furthermore, fndc3awue1/wue1 mutants display abnormal collagen localization, actinotrichia breakup and cellular defects in epidermal cells during caudal fin development. The observed effects are only temporary and later result in rather normal fin development in adults. In accordance with early fin development, proper caudal fin regeneration in adult fndc3awue1/wue1 mutants is hampered by interference with actinotrichia formation and epidermal cell abnormalities. Investigation of cellular matrix formation implied that loss of ECM structure is a common cause for both phenotypes. Our results thereby provide a molecular link between Fndc3a function during both developmental processes in zebrafish and foreshadow Fndc3a as a novel temporal regulator of epidermal cell properties during extremity development in vertebrates.

developmental biology↗