Publications

We maintain this section to inform interested users about independent scientific studies conducted on MetaSystems products. We assume no responsibility or liability regarding the accuracy or correct use of the information or statements provided by external authors. The conclusions or statements expressed in the publications listed are those of the external authors or researchers. The publications may involve user-specific adaptations of MetaSystems products. They are not intended for diagnostic use. For publications covered by the Intended Purpose of Metafer or Ikaros, please refer to the respective instructions for use (IFU).

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Frontiers in microbiology, 15, 1449844
2024

Artificial intelligence applications in the diagnosis and treatment of bacterial infections.

Zhang, Xiaoyu, Zhang, Deng, Zhang, Xifan, Zhang, Xin

<p>The diagnosis and treatment of bacterial infections in the medical and public health field in the 21st century remain significantly challenging. Artificial Intelligence (AI) has emerged as a powerful new tool in diagnosing and treating bacterial infections. AI is rapidly revolutionizing epidemiological studies of infectious diseases, providing effective early warning, prevention, and control of outbreaks. Machine learning models provide a highly flexible way to simulate and predict the complex mechanisms of pathogen-host interactions, which is crucial for a comprehensive understanding of the nature of diseases. Machine learning-based pathogen identification technology and antimicrobial drug susceptibility testing break through the limitations of traditional methods, significantly shorten the time from sample collection to the determination of result, and greatly improve the speed and accuracy of laboratory testing. In addition, AI technology application in treating bacterial infections, particularly in the research and development of drugs and vaccines, and the application of innovative therapies such as bacteriophage, provides new strategies for improving therapy and curbing bacterial resistance. Although AI has a broad application prospect in diagnosing and treating bacterial infections, significant challenges remain in data quality and quantity, model interpretability, clinical integration, and patient privacy protection. To overcome these challenges and, realize widespread application in clinical practice, interdisciplinary cooperation, technology innovation, and policy support are essential components of the joint efforts required. In summary, with continuous advancements and in-depth application of AI technology, AI will enable doctors to more effectivelyaddress the challenge of bacterial infection, promoting the development of medical practice toward precision, efficiency, and personalization; optimizing the best nursing and treatment plans for patients; and providing strong support for public health safety.</p>

Digital object identifier (DOI): 10.3389/fmicb.2024.1449844

Biomarker insights, 19, 11772719241274017
2024

The Chromosome Passenger Complex (CPC) Components and Its Associated Pathways Are Promising Candidates to Differentiate Between Normosensitive and Radiosensitive ATM-Mutated Cells.

Dietz, Anne, Subedi, Prabal, Azimzadeh, Omid, Duchrow, Lukas, Kaestle, Felix, Paetzold, Juliane, Katharina Payer, Sarah, Hornhardt, Sabine, von Toerne, Christine, Hauck, Stefanie M., Kempkes, Bettina, Kuklik-Roos, Cornelia, Brandes, Danielle, Borkhardt, Arndt, Moertl, Simone, Gomolka, Maria

<p>Sensitivity to ionizing radiation differs between individuals, but there is a limited understanding of the biological mechanisms that account for these variations. One example of such mechanisms are the mutations in the ATM (mutated ataxia telangiectasia) gene, that cause the rare recessively inherited disease Ataxia telangiectasia (AT). Hallmark features include chromosomal instability and increased sensitivity to ionizing radiation (IR). To deepen the molecular understanding of radiosensitivity and to identify potential new markers to predict it, human ATM-mutated and proficient cells were compared on a proteomic level. In this study, we analyzed 3 cell lines from AT patients, with varying radiosensitivity, and 2 cell lines from healthy volunteers, 24 hours and 72 hours post-10 Gy irradiation. We used label-free mass spectrometry to identify differences in signaling pathways after irradiation in normal and radiosensitive individuals. Cell viability was initially determined by water soluble tetrazolium (WST) assay and DNA damage response was analyzed with 53BP1 repair foci formation along with KRAB-associated protein 1 (KAP1) phosphorylation. Proteomic analysis identified 4028 proteins, which were used in subsequent in silico pathway enrichment analysis to predict affected biological pathways post-IR. In AT cells, networks were heterogeneous at both time points with no common pathway identified. Mitotic cell cycle progress was the most prominent pathway altered after IR in cells from healthy donors. In particular, components of the chromosome passenger complex (INCENP and CDCA8) were significantly downregulated after 72 hours. This could also be verified at the mRNA level. Altogether, the most striking result was that proteins forming the chromosome passenger complex were downregulated after radiation exposure in healthy normosensitive control cells, but not in radiosensitive ATM-deficient cells. Thus, mitosis-associated proteins form an interesting compound to gain insights into the development and prediction of radiosensitivity.</p>

Digital object identifier (DOI): 10.1177/11772719241274017

TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik, 138, 13
2024

Genotyping-by-sequencing uncovers a Thinopyrum 4StS·1J (vs)S Robertsonian translocation linked to multiple stress tolerances in bread wheat.

Klaudia Kruppa, Edina Türkösi, Kateřina Holušová, Balázs Kalapos, Éva Szakács et al.

<p>GBS read coverage analysis identified a Robertsonian chromosome from two Thinopyrum subgenomes in wheat, conferring leaf and stripe rust resistance, drought tolerance, and maintaining yield stability. Agropyron glael (GLAEL), a Thinopyrum intermedium\u8201?\u215?\u8201?Th. ponticum hybrid, serves as a valuable genetic resource for wheat improvement. Despite its potential, limited knowledge of its chromosome structure and homoeologous relationships with hexaploid wheat (Triticum aestivum) has restricted the full exploitation of GLAEL's genetic diversity in breeding programs. Here, we present the development of a 44-chromosome wheat/GLAEL addition line (GLA7). Multicolor genomic in situ hybridization identified one chromosome arm from the St subgenome of Th. intermedium, while the other arm remained unclassified. Genotyping-by-sequencing (GBS) read coverage analysis revealed a unique Robertsonian translocation between two distinct Thinopyrum subgenomes, identified as 4StS\u183?1J (vs)S. The GLA7 line demonstrated strong adult plant resistance to both leaf rust and stripe rust under natural and artificial infection conditions. Automated phenotyping of shoot morphological parameters together with leaf relative water content and yield components showed that the GLA7 line exhibited elevated drought tolerance compared to parental wheat genotypes. Three years of field trials showed that GLA7 exhibits similar agronomic performance and yield components to the wheat parents. This unique addition line holds promise for enhancing wheat's tolerance to multiple stresses through the introduction of new resistance genes, as well as its ability to mitigate the effects of temporary water limitation during flowering, all without negatively impacting wheat performance.</p>

Digital object identifier (DOI): 10.1007/s00122-024-04791-x

Journal of Genetic Engineering and Biotechnology, 22, 100409
2024

Potentials of cytokinesis blocked micronucleus assay in radiation triage and biological dosimetry.

G. Tamizh Selvan, P. Venkatachalam

<p>The measurement of micronucleus (MN) in the cytokinesis-block arrested binucleated cells has been extensively used as a biomarker in many radiation biology applications in specific biodosimetry. Following radiation casualties, medical management of exposed individuals begins with triage and biological dosimetry. The cytokinesis blocked micronucleus (CBMN) assay is the alternate for the gold standard dicentric chromosome assay in radiation dose assessment. In recent years, the CBMN assay has become well-validated and emerged as a method of choice for evaluating occupational and accidental exposures scenario. It is feasible due to its cost-effective, simple, and rapid dose assessment rather than a conventional chromosome aberration assay. PubMed search tool was used with keywords of MN, biodosimetry, radiotherapy and restricted to human samples. Since Fenech and Morely developed the assay, it has undergone many technical and technological reforms as a biomarker of various applications. In this review, we have abridged recent developments of the CBMN assay in radiation triage and biodosimetry, focusing on (a) the influence of variables on dose estimation, (b) the importance of baseline frequency and reported dose-response coefficient values among different laboratories, (c) inter-laboratory comparison and (d) its limitations and means to overcome them.</p>

Digital object identifier (DOI): 10.1016/j.jgeb.2024.100409

Particle and Fibre Toxicology, 21
2024

Determining the toxicological effects of indoor air pollution on both a healthy and an inflammatory-comprised model of the alveolar epithelial barrier in vitro

Kirsty Meldrum, Stephen J. Evans, Michael J. Burgum, Shareen H. Doak, Martin J. D. Clift

<p>Exposure to indoor air pollutants (IAP) has increased recently, with people spending more time indoors (i.e. homes, offices, schools and transportation). Increased exposures of IAP on a healthy population are poorly understood, and those with allergic respiratory conditions even less so. The objective of this study, therefore, was to implement a well-characterised in vitro model of the human alveolar epithelial barrier (A549 + PMA differentiated THP-1 incubated with and without IL-13, IL-5 and IL-4) to determine the effects of a standardised indoor particulate (NIST 2583) on both a healthy lung model and one modelling a type-II (stimulated with IL-13, IL-5 and IL-4) inflammatory response (such as asthma).Using concentrations from the literature, and an environmentally appropriate exposure we investigated 232, 464 and 608ng/cm<sup>2</sup> of NIST 2583 respectively. Membrane integrity (blue dextran), viability (trypan blue), genotoxicity (micronucleus (Mn) assay) and (pro-)/(anti-)inflammatory effects (IL-6, IL-8, IL-33, IL-10) were then assessed 24 h post exposure to both models. Models were exposed using a physiologically relevant aerosolisation method (VitroCell Cloud 12 exposure system).No changes in Mn frequency or membrane integrity in either model were noted when exposed to any of the tested concentrations of NIST 2583. A significant decrease (p &lt; 0.05) in cell viability at the highest concentration was observed in the healthy model. Whilst cell viability in the "inflamed" model was decreased at the lower concentrations (significantly (p &lt; 0.05) after 464ng/cm<sup>2</sup>). A significant reduction (p &lt; 0.05) in IL-10 and a significant increase in IL-33 was seen after 24 h exposure to NIST 2583 (464, 608ng/cm<sup>2</sup>) in the "inflamed" model.Collectively, the results indicate the potential for IAP to cause the onset of a type II response as well as exacerbating pre-existing allergic conditions. Furthermore, the data imposes the importance of considering unhealthy individuals when investigating the potential health effects of IAP. It also highlights that even in a healthy population these particles have the potential to induce this type II response and initiate an immune response following exposure to IAP.</p>

Digital object identifier (DOI): 10.1186/s12989-024-00584-8

iScience, 27, 111108
2024

Preclinical validation of human recombinant glutamate-oxaloacetate transaminase for the treatment of acute ischemic stroke

María Pérez-Mato, Antonio Dopico-López, Yunus Akkoc, Sonia López-Amoedo, Clara Correa-Paz et al.

<p>The blood enzyme glutamate-oxaloacetate transaminase (GOT) has been postulated as an effective therapeutic to protect the brain during stroke. To demonstrate its potential clinical utility, a new human recombinant form of GOT (rGOT) was produced for medical use. We tested the pharmacokinetics and evaluated the protective efficacy of rGOT in rodent and non-human primate models that reflected clinical stroke conditions. We found that continuous intravenous administration of rGOT within the first 8 h after ischemic onset significantly reduced the infarct size in both severe (30%) and mild lesions (48%). Cerebrospinal fluid and proteomics analysis, in combination with positron emission tomography imaging, indicated that rGOT can reach the brain and induce cytoprotective autophagy and induce local protection by alleviating neuronal apoptosis. Our results suggest that rGOT can be safely used immediately in patients suspected of having a stroke. This study requires further validation in clinical stroke populations.</p>

Digital object identifier (DOI): 10.1016/j.isci.2024.111108

PLOS ONE, 19, e0315183
2024

Enhanced detection of distinct honeycomb-structured neuronal SMARCC2 cytobodies in Parkinson’s Disease via Cyclic Heat-Induced Epitope Retrieval (CHIER)

Amber Carmichael-Lowe, Brionne Fleming, Kreesan Reddy, James Wiseman, Eden Paige Yin et al.

<p>Antigen retrieval is crucial for immunohistochemistry, particularly in formalin-fixed paraffin-embedded brain tissue, where fixation causes extensive crosslinking that masks epitopes. Heat Induced Epitope Retrieval (HIER) reverses these crosslinks, improving access to nuclear and aggregated proteins. We introduce Cyclic Heat-Induced Epitope Retrieval (CHIER), an advanced technique that builds on HIER by incorporating repeated cycles of heating and cooling. CHIER optimises antigen retrieval and significantly improves detection. CHIER is particularly effective for detecting chromatin-binding proteins, such as SMARCC2, which are difficult to label using conventional IHC methods. Using CHIER on formalin-fixed paraffin-embedded human brain sections, we achieved robust detection of SMARCC2 in both the nucleus and cytoplasm. CHIER also enhanced the visualisation of large SMARCC2+ cytoplasmic bodies, termed cytobodies, which are increased in Parkinson’s Disease (PD). Our findings suggest that SMARCC2 may translocate from the nucleus to the cytoplasm in PD, potentially implicating SMARCC2 aggregation in the disease’s pathology. Furthermore, CHIER does not negatively impact the antigenicity of other antibodies, supporting its use for multiplex fluorescent immunohistochemistry and super-resolution imaging. These results highlight CHIER’s potential for improving the detection of chromatin-binding and aggregated proteins in neurodegenerative disease research, offering new insights into SMARCC2’s role in Parkinson’s Disease.</p>

Digital object identifier (DOI): 10.1371/journal.pone.0315183

Cancer Research, 84, 2856-2872
2024

RUVBL1/2 Blockade Targets YTHDF1 Activity to Suppress m6A-Dependent Oncogenic Translation and Colorectal Tumorigenesis

Danyu Chen, Fenfen Ji, Qiming Zhou, Henley Cheung, Yasi Pan et al.

<p>The N<sup>6</sup>-methyladenosine (m<sup>6</sup>A) RNA-binding protein YTHDF1 is frequently overexpressed in colorectal cancer and drives chemotherapeutic resistance. To systematically identify druggable targets in colorectal cancer with high expression of YTHDF1, this study used a CRISPR/Cas9 screening strategy that revealed RUVBL1 and RUVBL2 as putative targets. RUVBL1/2 were overexpressed in primary colorectal cancer samples and represented independent predictors of poor patient prognosis. Functionally, loss of RUVBL1/2 preferentially impaired the growth of YTHDF1-high colorectal cancer cells, patient-derived primary colorectal cancer organoids, and subcutaneous xenografts. Mechanistically, YTHFD1 and RUVBL1/2 formed a positive feedforward circuit to accelerate oncogenic translation. YTHDF1 bound to m<sup>6</sup>A-modified RUVBL1/2 mRNA to promote translation initiation and protein expression. Coimmunoprecipitation and mass spectrometry identified that RUVBL1/2 reciprocally interacted with YTHDF1 at 40S translation initiation complexes. Consequently, RUVBL1/2 depletion stalled YTHDF1-driven oncogenic translation and nascent protein biosynthesis, leading to proliferative arrest and apoptosis. Ribosome sequencing revealed that RUVBL1/2 loss impaired the activation of MAPK, RAS, and PI3K-AKT signaling induced by YTHDF1. Finally, the blockade of RUVBL1/2 by the pharmacological inhibitor CB6644 or vesicle-like nanoparticle-encapsulated siRNAs preferentially arrested the growth of YTHDF1-expressing colorectal cancer <em>in vitro</em> and <em>in vivo</em>. Our findings show that RUVBL1/2 are potential prognostic markers and druggable targets that regulate protein translation in YTHDF1-high colorectal cancer.</p>

Digital object identifier (DOI): 10.1158/0008-5472.can-23-2081

Nature Communications, 15
2024

Dermal injury drives a skin to gut axis that disrupts the intestinal microbiome and intestinal immune homeostasis in mice

Tatsuya Dokoshi, Yang Chen, Kellen J. Cavagnero, Gibraan Rahman, Daniel Hakim et al.

<p>The composition of the microbial community in the intestine may influence the functions of distant organs such as the brain, lung, and skin. These microbes can promote disease or have beneficial functions, leading to the hypothesis that microbes in the gut explain the co-occurrence of intestinal and skin diseases. Here, we show that the reverse can occur, and that skin directly alters the gut microbiome. Disruption of the dermis by skin wounding or the digestion of dermal hyaluronan results in increased expression in the colon of the host defense genes <em>Reg3</em> and <em>Muc2</em>, and skin wounding changes the composition and behavior of intestinal bacteria. Enhanced expression <em>Reg3</em> and <em>Muc2</em> is induced in vitro by exposure to hyaluronan released by these skin interventions. The change in the colon microbiome after skin wounding is functionally important as these bacteria penetrate the intestinal epithelium and enhance colitis from dextran sodium sulfate (DSS) as seen by the ability to rescue skin associated DSS colitis with oral antibiotics, in germ-free mice, and fecal microbiome transplantation to unwounded mice from mice with skin wounds. These observations provide direct evidence of a skin-gut axis by demonstrating that damage to the skin disrupts homeostasis in intestinal host defense and alters the gut microbiome.</p>

Digital object identifier (DOI): 10.1038/s41467-024-47072-3

Advanced Science, 11
2024

Molecular Lineages and Spatial Distributions of Subplate Neurons in the Human Fetal Cerebral Cortex

Xueyu Guo, Trevor Lee, Jason Sun, Julianne Sun, Wenjie Cai et al.

<p>The expansion of neural progenitors and production of distinct neurons are crucial for architectural assembly and formation of connectivity in human brains. Subplate neurons (SPNs) are among the firstborn neurons in the human fetal cerebral cortex, and play a critical role in establishing intra- and extracortical connections. However, little is known about SPN origin and developmental lineages. In this study, spatial landscapes and molecular trajectories of SPNs in the human fetal cortices from gestational weeks (GW) 10 to 25 are created by performing spatial transcriptomics and single-cell RNA sequencing. Genes known to be evolutionarily human-specific and genes associated with extracellular matrices (ECMs) are found to maintain stable proportions of subplate neurons among other neuronal types. Enriched ECM gene expression in SPNs varies in distinct cortical regions, with the highest level in the frontal lobe of human fetal brains. This study reveals molecular origin and lineage specification of subplate neurons in the human fetal cerebral cortices, and highlights underpinnings of SPNs to cortical neurogenesis and early structural folding.</p>

Digital object identifier (DOI): 10.1002/advs.202407137

Molecular Psychiatry, 29, 2408-2423
2024

Scanning ultrasound-mediated memory and functional improvements do not require amyloid-β reduction

Gerhard Leinenga, Xuan Vinh To, Liviu-Gabriel Bodea, Jumana Yousef, Gina Richter-Stretton et al.

<p>A prevalent view in treating age-dependent disorders including Alzheimer’s disease (AD) is that the underlying amyloid plaque pathology must be targeted for cognitive improvements. In contrast, we report here that repeated scanning ultrasound (SUS) treatment at 1 MHz frequency can ameliorate memory deficits in the APP23 mouse model of AD without reducing amyloid-β (Aβ) burden. Different from previous studies that had shown Aβ clearance as a consequence of blood-brain barrier (BBB) opening, here, the BBB was not opened as no microbubbles were used. Quantitative SWATH proteomics and functional magnetic resonance imaging revealed that ultrasound induced long-lasting functional changes that correlate with the improvement in memory. Intriguingly, the treatment was more effective at a higher frequency (1 MHz) than at a frequency within the range currently explored in clinical trials in AD patients (286 kHz). Together, our data suggest frequency-dependent bio-effects of ultrasound and a dissociation of cognitive improvement and Aβ clearance, with important implications for the design of trials for AD therapies.</p>

Digital object identifier (DOI): 10.1038/s41380-024-02509-5

Nature Communications, 15
2024

Claustrum and dorsal endopiriform cortex complex cell-identity is determined by Nurr1 and regulates hallucinogenic-like states in mice

Ioannis Mantas, Ivana Flais, Yuvarani Masarapu, Tudor Ionescu, Solène Frapard et al.

<p>The Claustrum/dorsal endopiriform cortex complex (CLA) is an enigmatic brain region with extensive glutamatergic projections to multiple cortical areas. The transcription factor Nurr1 is highly expressed in the CLA, but its role in this region is not understood. By using conditional gene-targeted mice, we show that Nurr1 is a crucial regulator of CLA neuron identity. Although CLA neurons remain intact in the absence of Nurr1, the distinctive gene expression pattern in the CLA is abolished. CLA has been hypothesized to control hallucinations, but little is known of how the CLA responds to hallucinogens. After the deletion of Nurr1 in the CLA, both hallucinogen receptor expression and signaling are lost. Furthermore, functional ultrasound and Neuropixel electrophysiological recordings revealed that the hallucinogenic-receptor agonists’ effects on functional connectivity between prefrontal and sensorimotor cortices are altered in Nurr1-ablated mice. Our findings suggest that Nurr1-targeted strategies provide additional avenues for functional studies of the CLA.</p>

Digital object identifier (DOI): 10.1038/s41467-024-52429-9

2024

Αlpha-Synuclein Induced Immune Response Triggers Parkinson’s Disease-Like Symptoms

Rebekah G. Parkinson, Tony Xu, Jacob Martin, Zizheng Xian, Ilvana Ziko et al.

<p>Increasing evidence suggests that Parkinson’s disease is an autoimmune disorder, with findings of elevated peripheral blood mononuclear cell in patients, and antigenic properties of α-synuclein driving both the innate and adaptive immunity. Yet, how the interaction of α-synuclein and a specific immune response participates to Parkinson’s disease ontogenesis has remained unanswered. Here, we reveal that autoimmune response to an α-synuclein antigen underlies Parkinson’s disease. We demonstrate that autoimmunity mediated by CD4+T cell activation with α-synuclein α-syn<sub>61-75</sub> antigen is required to lead to immune cell infiltration and localized inflammation in the substantia nigra, triggering dopaminergic cell neurodegeneration and deficits in locomotion and gait kinematics. This study offers the first immune-induced mouse model that recapitulates all features of Parkinson’s disease to study the mechanisms triggering disease onset. It provides the basis for temporally tracking symptom development, exploring preventive strategies and prodromal therapeutic interventions in Parkinson’s Disease.</p>

Digital object identifier (DOI): 10.1101/2024.05.27.596130

Cancer Discovery, 15, 83-104
2024

Chromothripsis-Mediated Small Cell Lung Carcinoma

Natasha Rekhtman, Sam E. Tischfield, Christopher A. Febres-Aldana, Jake June-Koo Lee, Jason C. Chang et al.

<p>Small cell lung carcinoma (SCLC) is a highly aggressive malignancy that is typically associated with tobacco exposure and inactivation of <em>RB1</em> and <em>TP53</em> genes. Here, we performed detailed clinicopathologic, genomic, and transcriptomic profiling of an atypical subset of SCLC that lacked <em>RB1</em> and <em>TP53</em> co-inactivation and arose in never/light smokers. We found that most cases were associated with chromothripsis—massive, localized chromosome shattering—recurrently involving chromosome 11 or 12 and resulting in extrachromosomal amplification of <em>CCND1</em> or co-amplification of <em>CCND2</em>/<em>CDK4</em>/<em>MDM2</em>, respectively. Uniquely, these clinically aggressive tumors exhibited genomic and pathologic links to pulmonary carcinoids, suggesting a previously uncharacterized mode of SCLC pathogenesis via transformation from lower-grade neuroendocrine tumors or their progenitors. Conversely, SCLC in never-smokers harboring inactivated <em>RB1</em> and <em>TP53</em> exhibited hallmarks of adenocarcinoma-to-SCLC derivation, supporting two distinct pathways of plasticity-mediated pathogenesis of SCLC in never-smokers.</p> <p><strong>Significance:</strong> Here, we provide the first detailed description of a unique SCLC subset lacking <em>RB1</em>/<em>TP53</em> alterations and identify extensive chromothripsis and pathogenetic links to pulmonary carcinoids as its hallmark features. This work defines atypical SCLC as a novel entity among lung cancers, highlighting its exceptional histogenesis, clinicopathologic characteristics, and therapeutic vulnerabilities.</p>

Digital object identifier (DOI): 10.1158/2159-8290.cd-24-0286

Neurotrauma Reports, 5, 194-202
2024

Histological Characterisation of a Sheep Model of Mild Traumatic Brain Injury: A Pilot Study

Sheryl Tan, Danica Hamlin, Eryn Kwon, Miriam Scadeng, Vickie Shim et al.

<p>Large animal models of mild traumatic brain injury (mTBI) are needed to elucidate the pathophysiology of mechanical insult to a gyrencephalic brain. Sheep (ovis aries) are an attractive model for mTBI because of their neuroanatomical similarity to humans; however, few histological studies of sheep mTBI models have been conducted. We previously developed a sheep mTBI model to pilot methods for investigating the mechanical properties of brain tissue after injury. Here, we sought to histologically characterize the cortex under the impact site in this model. Three animals received a closed skull mTBI with unconstrained head motion, delivered with an impact stunner, and 3 sham animals were anesthetized but did not receive an impact. Magnetic resonance imaging (MRI) of the brain was performed before and after the impact and revealed variable degrees of damage to the skull and brain. Fluorescent immunohistochemistry revealed regions of hemorrhage in the cortex underlying the impact site in 2 of 3 mTBI sheep, the amount of which correlated with the degree of damage observed on the post-impact MRI scans. Labeling for microtubule-associated protein 2 and neuronal nuclear protein revealed changes in cellular anatomy, but, unexpectedly, glial fibrillary acidic protein and ionized calcium-binding adaptor molecule 1 labeling were relatively unchanged compared to sham animals. Our findings provide preliminary evidence of vascular and neuronal damage with limited glial reactivity and highlight the need for further in-depth histological assessment of large animal mTBI models.</p>

Digital object identifier (DOI): 10.1089/neur.2023.0105

Brain, 147, 3547-3561
2024

Hippocampal aggregation signatures of pathogenic UBQLN2 in amyotrophic lateral sclerosis and frontotemporal dementia

Kyrah M. Thumbadoo, Birger V. Dieriks, Helen C. Murray, Molly E. V. Swanson, Ji Hun Yoo et al.

<p>Pathogenic variants in the <em>UBQLN2</em> gene cause X-linked dominant amyotrophic lateral sclerosis and/or frontotemporal dementia characterized by ubiquilin 2 aggregates in neurons of the motor cortex, hippocampus and spinal cord. However, ubiquilin 2 neuropathology is also seen in sporadic and familial amyotrophic lateral sclerosis and/or frontotemporal dementia cases not caused by <em>UBQLN2</em> pathogenic variants, particularly <em>C9orf72</em>-linked cases. This makes the mechanistic role of mutant ubiquilin 2 protein and the value of ubiquilin 2 pathology for predicting genotype unclear. Here we examine a cohort of 44 genotypically diverse amyotrophic lateral sclerosis cases with or without frontotemporal dementia, including eight cases with <em>UBQLN2</em> variants [resulting in p.S222G, p.P497H, p.P506S, p.T487I (two cases) and p.P497L (three cases)].</p> <p>Using multiplexed (five-label) fluorescent immunohistochemistry, we mapped the co-localization of ubiquilin 2 with phosphorylated TDP-43, dipeptide repeat aggregates and p62 in the hippocampus of controls (<em>n</em> = 6), or amyotrophic lateral sclerosis with or without frontotemporal dementia in sporadic (<em>n</em> = 20), unknown familial (<em>n</em> = 3), <em>SOD1</em>-linked (<em>n</em> = 1), <em>FUS</em>-linked (<em>n</em> = 1), <em>C9orf72</em>-linked (<em>n</em> = 5) and <em>UBQLN2</em>-linked (<em>n</em> = 8) cases.</p> <p>We differentiate between (i) ubiquilin 2 aggregation together with phosphorylated TDP-43 or dipeptide repeat proteins; and (ii) ubiquilin 2 self-aggregation promoted by <em>UBQLN2</em> pathogenic variants that cause amyotrophic lateral sclerosis and/or frontotemporal dementia. Overall, we describe a hippocampal protein aggregation signature that fully distinguishes mutant from wild-type ubiquilin 2 in amyotrophic lateral sclerosis with or without frontotemporal dementia, whereby mutant ubiquilin 2 is more prone than wild-type to aggregate independently of driving factors.</p> <p>This neuropathological signature can be used to assess the pathogenicity of <em>UBQLN2</em> gene variants and to understand the mechanisms of <em>UBQLN2</em>-linked disease.</p>

Digital object identifier (DOI): 10.1093/brain/awae140

Brain, Behavior, and Immunity, 117, 181-194
2024

ROCK2 regulates microglia proliferation and neuronal survival after traumatic brain injury

Emily F. Willis, Seung Jae Kim, Wei Chen, Melanie Nyuydzefe, Kelli P. A. MacDonald et al.

<p>Traumatic brain injury (TBI) results in prolonged and non-resolving activation of microglia. Forced turnover of these cells during the acute phase of <a href="https://www.sciencedirect.com/topics/neuroscience/traumatic-brain-injury" title="Learn more about TBI from ScienceDirect's AI-generated Topic Pages">TBI</a> aids recovery, but the cell-intrinsic pathways that underpin the pro-repair phenotype of these repopulating microglia remain unclear. Here, we show that selective targeting of ROCK2 with the small molecule inhibitor KD025 impairs the proliferative response of microglia after TBI as well as during genetically induced turnover of microglia. KD025 treatment abolished the substantial neuroprotective and cognitive benefits conferred by repopulating microglia, preventing these cells from replenishing the depleted niche during the early critical time window post-injury. Delaying KD025 treatment to the subacute phase of TBI allowed microglial repopulation to occur, but this did not enhance the benefits conferred by repopulating microglia. Taken together, our data indicate that ROCK2 mediates neuronal survival and microglial population dynamics after TBI, including the emergence of repopulating microglia with a pro-repair phenotype.</p>

Digital object identifier (DOI): 10.1016/j.bbi.2024.01.004

npj Parkinson’s Disease, 10
2024

Aggregate-prone brain regions in Parkinson’s disease are rich in unique N-terminus α-synuclein conformers with high proteolysis susceptibility

James A. Wiseman, Helen C. Murray, Richard L. M. F. Faull, Michael Dragunow, Clinton P. Turner et al.

<p>In Parkinson’s disease (PD), and other α-synucleinopathies, α-synuclein (α-Syn) aggregates form a myriad of conformational and truncational variants. Most antibodies used to detect and quantify α-Syn in the human brain target epitopes within the C-terminus (residues 96–140) of the 140 amino acid protein and may fail to capture the diversity of α-Syn variants present in PD. We sought to investigate the heterogeneity of α-Syn conformations and aggregation states in the PD human brain by labelling with multiple antibodies that detect epitopes along the entire length of α-Syn. We used multiplex immunohistochemistry to simultaneously immunolabel tissue sections with antibodies mapping the three structural domains of α-Syn. Discrete epitope-specific immunoreactivities were visualised and quantified in the olfactory bulb, medulla, substantia nigra, hippocampus, entorhinal cortex, middle temporal gyrus, and middle frontal gyrus of ten PD cases, and the middle temporal gyrus of 23 PD, and 24 neurologically normal cases. Distinct Lewy neurite and Lewy body aggregate morphologies were detected across all interrogated regions/cases. Lewy neurites were the most prominent in the olfactory bulb and hippocampus, while the substantia nigra, medulla and cortical regions showed a mixture of Lewy neurites and Lewy bodies. Importantly, unique N-terminus immunoreactivity revealed previously uncharacterised populations of (1) perinuclear, (2) glial (microglial and astrocytic), and (3) neuronal lysosomal α-Syn aggregates. These epitope-specific N-terminus immunoreactive aggregate populations were susceptible to proteolysis via time-dependent proteinase K digestion, suggesting a less stable oligomeric aggregation state. Our identification of unique N-terminus immunoreactive α-Syn aggregates adds to the emerging paradigm that α-Syn pathology is more abundant and complex in human brains with PD than previously realised. Our findings highlight that labelling multiple regions of the α-Syn protein is necessary to investigate the full spectrum of α-Syn pathology and prompt further investigation into the functional role of these N-terminus polymorphs.</p>

Digital object identifier (DOI): 10.1038/s41531-023-00614-w

International journal of molecular sciences, 24
March, 2023

High Resolution and Automatable Cytogenetic Biodosimetry Using In Situ Telomere and Centromere Hybridization for the Accurate Detection of DNA Damage: An Overview.

M'Kacher, Radhia, Colicchio, Bruno, Junker, Steffen, El Maalouf, Elie, Heidingsfelder, Leonhard, Plesch, Andreas, Dieterlen, Alain, Jeandidier, Eric, Carde, Patrice, Voisin, Philippe

<p>In the event of a radiological or nuclear accident, or when physical dosimetry is not available, the scoring of radiation-induced chromosomal aberrations in lymphocytes constitutes an essential tool for the estimation of the absorbed dose of the exposed individual and for effective triage. Cytogenetic biodosimetry employs different cytogenetic assays including the scoring of dicentrics, micronuclei, and translocations as well as analyses of induced premature chromosome condensation to define the frequency of chromosome aberrations. However, inherent challenges using these techniques include the considerable time span from sampling to result, the sensitivity and specificity of the various techniques, and the requirement of highly skilled personnel. Thus, techniques that obviate these challenges are needed. The introduction of telomere and centromere (TC) staining have successfully met these challenges and, in addition, greatly improved the efficiency of cytogenetic biodosimetry through the development of automated approaches, thus reducing the need for specialized personnel. Here, we review the role of the various cytogenetic dosimeters and their recent improvements in the management of populations exposed to genotoxic agents such as ionizing radiation. Finally, we discuss the emerging potentials to exploit these techniques in a wider spectrum of medical and biological applications, e.g., in cancer biology to identify prognostic biomarkers for the optimal triage and treatment of patients.</p>

Digital object identifier (DOI): 10.3390/ijms24065699