Biology subjects

Hill, M.

Publications and source records attributed to Hill, M..

54 records · Page 3Linked to original sources

bioRxiv2022

Sugar shock: Probing Streptococcus pyogenes metabolism through bioluminescence imaging

Streptococcus pyogenes (S. pyogenes) can thrive in its host during an infection, and, as a result, it must be able to respond to external stimuli and available carbon sources. The preclinical use of engineered pathogens capable of constitutive light production may provide realtime information on microbial-specific metabolic processes. Here we mapped the central metabolism of a luxABCDE-modified S. pyogenes Xen20 (Strep. Xen20) to its de novo synthesis of luciferase substrates as assessed by the rate of light production in response to different environmental triggers. Previous characterization predicted that the lux operon was under the myo-inositol iolE promotor. Here we show that supplementation with myoinositol generated increased Xen20 luminescence. Surprisingly, when supplemented with infection-relevant carbon sources, such as glucose or glycine, light production was diminished. This was presumably due to the scavenging of pyruvate by L-lactate dehydrogenase (LDH). Inhibition of LDH by its inhibitor, oxamate, partially restored luminescent signal in the presence of glucose, presumably by allowing the resulting pyruvate to proceed to acetyl-coenzyme A (CoA). This phenomenon appeared specific to the lactic acid bacterial metabolism as glucose or glycine did not reduce signal in an analogous luxABCDE-modified Gram-positive pathogen, Staph. Xen29. The Strep. Xen20 cells produced light in a concentration-dependent manner, inversely related to the amount of glucose present. Taken together, our measures of microbial response could provide new information regarding the responsiveness of S. pyogenes metabolism to acute changes in its local environments and cellular health.

microbiology↗

bioRxiv2021

On the Effect of Intralocus Recombination on Triplet-Based Species Tree Estimation

We consider species tree estimation from multiple loci subject to intralocus recombination. We focus on R*, a summary coalescent-based methods using rooted triplets. We demonstrate analytically that intralocus recombination gives rise to an inconsistency zone, in which correct inference is not assured even in the limit of infinite amount of data. In addition, we validate and characterize this inconsistency zone through a simulation study that suggests that differential rates of recombination between closely related taxa can amplify the effect of incomplete lineage sorting and contribute to inconsistency.

evolutionary biology↗

bioRxiv2021

Controlling pallidal oscillations in real-time in Parkinson's disease using evoked interference deep brain stimulation (eiDBS): proof of concept in the human

Approaches to control basal ganglia neural activity in real-time are needed to clarify the causal role of 8-35 Hz ("beta band") oscillatory dynamics in the manifestation of Parkinsons disease (PD) motor signs. Here, we show that resonant beta oscillations evoked by electrical pulse with precise amplitude and timing can be used to predictably suppress or amplify spontaneous beta band activity in the internal segment of the globus pallidus (GPi) in the human. Using this approach, referred to as closed-loop evoked interference deep brain stimulation (eiDBS), we could suppress or amplify frequencyspecific (16-22 Hz) neural activity in a PD patient. Our results highlight the utility of eiDBS to characterize the role of oscillatory dynamics in PD and other brain conditions, and to develop personalized neuromodulation systems.

neuroscience↗

bioRxiv2021

Modest changes in Spi1 dosage reveal the potential for altered microglial function as seen in Alzheimers disease

Genetic association studies have identified multiple variants at the SPI1 locus that modify risk and age of onset for Alzheimers Disease (AD). Reports linking risk variants to gene expression suggest that variants denoting higher SPI1 expression are likely to have an earlier AD onset, and several other AD risk genes contain PU.1 binding sites in the promoter region. Overall, this suggests altered levels of SPi1 may alter microglial phenotype potentially impacting AD. This study determined how the mouse microglial transcriptome was altered following modest changes to Spi1 expression in primary microglia. RNA-sequencing was performed on microglia with reduced or increased Spi1/PU.1 expression to provide an unbiased approach to determine transcriptomic changes affected by Spi1. In summary, a reduction in microglial Spi1 resulted in the dysregulation of transcripts encoding proteins involved in DNA replication pathways while an increased Spi1 results in an upregulation of genes associated with immune response pathways. Additionally, a subset of 194 Spi1 dose-sensitive genes was identified and pathway analysis suggests that several innate immune and interferon response pathways are impacted by the concentration of Spi1. Together these results suggest Spi1 levels can alter the microglial transcriptome and suggests interferon pathways may be altered in individuals with AD related Spi1 risk SNPs.

neuroscience↗

bioRxiv2020

Ivermectin reduces coronavirus infection in vivo: a mouse experimental model

SARS-CoV2 is a single strand RNA virus member of the type 2 coronavirus family, responsible for causing COVID-19 disease in humans. The objective of this study was to test the ivermectin drug in a murine model of coronavirus infection using a type 2 family RNA coronavirus similar to SARS-CoV2, the mouse hepatitis virus (MHV). BALB/cJ female mice were infected with 6,000 PFU of MHV-A59 (Group Infected; n=20) and immediately treated with one single dose of 500 g/kg of ivermectin (Group Infected + IVM; n=20), or were not infected and treated with PBS (Control group; n=16). Five days after infection/treatment, mice were euthanized to obtain different tissues to check general health status and infection levels. Overall results demonstrated that viral infection induces the typical MHV disease in infected animals, with livers showing severe hepatocellular necrosis surrounded by a severe lymphoplasmacytic inflammatory infiltration associated with a high hepatic viral load (52,158 AU), while ivermectin administration showed a better health status with lower viral load (23,192 AU; p<0.05) and few livers with histopathological damage (p<0.05), not showing statistical differences with control mice (P=NS). Furthermore, serum transaminase levels (aspartate aminotransferase and alanine aminotransferase) were significantly lower in treated mice compared to infected animals. In conclusion, ivermectin seems to be effective to diminish MHV viral load and disease in mice, being a useful model for further understanding new therapies against coronavirus diseases.

pathology↗

bioRxiv2020

Freshwater sponge hosts and their green algae symbionts: a tractable model to understand intracellular symbiosis

In many freshwater habitats, green algae form intracellular symbioses with a variety of heterotrophic host taxa including several species of freshwater sponge. These sponges perform important ecological roles in their habitats, and the poriferan:green algae partnerships offers unique opportunities to study the evolutionary origins and ecological persistence of endosymbioses. We examined the association between Ephydatia muelleri and its chlorophyte partner to identify features of host cellular and genetic responses to the presence of intracellular algal partners. Chlorella-like green algal symbionts were isolated from field-collected adult E. muelleri tissue harboring algae. The sponge-derived algae were successfully cultured and subsequently used to reinfect aposymbiotic E. muelleri tissue. We used confocal microscopy to follow the fate of the sponge-derived algae after inoculating algae-free E. muelleri grown from gemmules to show temporal patterns of symbiont location within host tissue. We also infected aposymbiotic E. muelleri with sponge-derived algae, and performed RNASeq to study differential expression patterns in the host relative to symbiotic states. We compare and contrast our findings with work in other systems (e.g., endosymbiotic Hydra) to explore possible conserved evolutionary pathways that may lead to stable mutualistic endosymbioses. Our work demonstrates that freshwater sponges offer many tractable qualities to study features of intracellular occupancy and thus meet criteria desired for a model system.

evolutionary biology↗

bioRxiv2020

Structure of human endo-α-1,2-mannosidase (MANEA), an antiviral host-glycosylation target

Mammalian protein N-linked glycosylation is critical for glycoprotein folding, quality control, trafficking, recognition and function. N-linked glycans are synthesized from Glc3Man9GlcNAc2 precursors that are trimmed and modified in the endoplasmic reticulum (ER) and Golgi apparatus by glycoside hydrolases and glycosyltransferases. Endo--1,2-mannosidase (MANEA) is the sole endo-acting glycoside hydrolase involved in N-glycan trimming and unusually is located within the Golgi, where it allows ER escaped glycoproteins to bypass the classical N-glycosylation trimming pathway involving ER glucosidases I and II. There is considerable interest in the use of small molecules that disrupt N-linked glycosylation as therapeutic agents for diseases such as cancer and viral infection. Here we report the structure of the catalytic domain of human MANEA and complexes with substrate-derived inhibitors, which provide insight into dynamic loop movements that occur upon substrate binding. We reveal structural features of the human enzyme that explain its substrate preference and the mechanistic basis for catalysis. The structures inspired the development of new inhibitors that disrupted host protein N-glycan processing of viral glycans and reduced infectivity of bovine viral diarrhea and dengue viruses in cellular models. These results may contribute to efforts of developing broad-spectrum antiviral agents and bring about a more detailed view of the biology of mammalian glycosylation. SIGNIFICANCE STATEMENTThe glycosylation of proteins is a major protein modification that occurs extensively in eukaryotes. Glycosidases in the secretory pathway that trim N-linked glycans play a key role in protein quality control and in the specific modifications leading to mature glycoproteins. Inhibition of glucosidases in the secretory pathway is a proven therapeutic strategy, and one with great promise in the treatment of viral disease. The enzyme endo--1,2-mannosidase, MANEA, provides an alternative processing pathway to evade glucosidase inhibitors. We report the 3D structure of human MANEA and complexes with enzyme inhibitors that we show act as antivirals for bovine viral diarrhea and human dengue viruses. The structure of MANEA will support inhibitor optimization and the development of more potent antivirals.

biochemistry↗

bioRxiv2020

High-frequency oscillations in the internal globus pallidus: a pathophysiological biomarker in Parkinson's disease?

Abnormal oscillatory neural activity in the basal ganglia is thought to play a pathophysiological role in Parkinsons disease. Many patient studies have focused on beta frequency band (13-35 Hz) local field potential activity in the subthalamic nucleus, however increasing evidence points to alterations in neural oscillations in high frequency ranges (>100 Hz) having pathophysiological relevance. Prior studies have found that power in subthalamic high frequency oscillations (HFOs) is positively correlated with dopamine tone and increased during voluntary movements, implicating these brain rhythms in normal basal ganglia function. Contrary to this idea, in the current study we present a combination of clinical and preclinical data that support the hypothesis that HFOs in the internal globus pallidus (GPi) are a pathophysiological feature of Parkinsons disease. Spontaneous and movement-related pallidal field potentials were recorded from deep brain stimulation (DBS) leads targeting the GPi in five externalized Parkinsons disease patients, on and off dopaminergic medication. We identified a prominent oscillatory peak centered at 200-300 Hz in the off-medication rest recordings in all patients. High frequency power increased during movement, and the magnitude of modulation was negatively correlated with bradykinesia. Moreover, high frequency oscillations were significantly attenuated in the on-medication condition, suggesting they are a feature of the parkinsonian condition. To further confirm that GPi high frequency oscillations are characteristic of dopamine depletion, we also collected field potentials from DBS leads chronically implanted in three rhesus monkeys before and after the induction of parkinsonism with the neurotoxin 1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine (MPTP). High frequency oscillations and their modulation during movement were not prominent in the normal condition but emerged in the parkinsonian condition in the monkey model. These data provide the first evidence demonstrating that exaggerated, movement-modulated high frequency oscillations in the internal globus pallidus are a pathophysiological feature of Parkinsons disease, and motivate additional investigations into the functional roles of high frequency neural oscillations across the basal ganglia-thalamocortical motor circuit and their relationship to motor control in normal and diseased states. These findings also provide rationale for further exploration of these signals for electrophysiological biomarker-based device programming and stimulation strategies in patients receiving deep brain stimulation therapy.

neuroscience↗

bioRxiv2020

Microbiome structure of ecologically important bioeroding sponges (family Clionaidae): The role of host phylogeny and environmental plasticity.

The potential of increased bioerosion by excavating sponges in future environmental scenarios represents a potential threat to coral reef structure and function. If we are to predict changes to coral reef habitats, it is important to understand the biology of these sponges. Little is known about prokaryotic associations in excavating sponges despite the fact that evidence indicates they contribute to the sponge growth through their heterotrophic metabolism and may even act as microborers. Here, we provide the first detailed description of the microbial community of multiple bioeroding sponges from the Clionaidae family (Cliona varians, C. tumula, C. delitrix, Spheciospongia vesparium, Cervicornia cuspidifera) collected in inshore and offshore coral reefs in the Florida Keys. A total of 6,811 prokaryote OTUs identified using 16S rRNA gene sequencing was detected in the samples studied, including ambient water, belonging to 39 bacterial phyla and 3 archaeal phyla. The microbiomes of species harboring Symbiodinium (Cliona varians, C. tumula, Cervicornia cuspidifera) and the azooxanthellate S. vesparium were dominated by Alphaproteobacteria that represented from 83 to 96% of total sequences. These clionaid sponges presented species-specific core microbiomes, with 4 OTUs being shared by all sponge samples, albeit with species-specific enrichments. The microbiomes of C. varians and S. vesparium were stable but showed certain plasticity between offshore and inshore reefs. The distantly related Cliona delitrix does not harbor Symbiodinium, and had a microbiome dominated by Gammaproteobacteria, which represented 82% of all sequences. Most of the sponge-exclusive OTUs are found in low abundance and belong to the "rare biosphere" category, highlighting the potential importance of these microbes in the ecology of the holobiont. Sponge microbiomes may enhance functional redundancy for the sponge holobiont and allow it to respond to shifting environments over much short time scales than evolutionary change would permit. This work establishes the basis for future research to explore how microbial shifts in bioeroding sponges contribute to bioerosion in the face of a changing environment.

ecology↗

bioRxiv2020

Fragmentation of extracellular ribosomes and tRNAs shapes the extracellular RNAome

A major proportion of extracellular RNAs (exRNAs) do not co-isolate with extracellular vesicles (EVs) and remain in ultracentrifugation supernatants of cell-conditioned medium or mammalian blood serum. However, little is known about exRNAs beyond EVs. We have previously shown that the composition of the nonvesicular exRNA fraction is highly biased toward specific tRNA-derived fragments capable of forming RNase-protecting dimers. To solve the problem of stability in exRNA analysis, we developed RI-SEC-seq: a method based on sequencing the size exclusion chromatography (SEC) fractions of nonvesicular extracellular samples treated with RNase inhibitors (RI). This method revealed dramatic compositional changes in exRNA population when enzymatic RNA degradation was inhibited. We demonstrated the presence of ribosomes and full-length tRNAs in cell-conditioned medium of a variety of mammalian cell lines. Their fragmentation generates some small RNAs that are highly resistant to degradation. The extracellular biogenesis of some of the most abundant exRNAs demonstrates that extracellular abundance is not a reliable input to estimate RNA secretion rates. Finally, we showed that chromatographic fractions containing extracellular ribosomes can be sensed by dendritic cells. Extracellular ribosomes and/or tRNAs could therefore be decoded as damage-associated molecular patterns.

cell biology↗

bioRxiv2019

Ongoing repair of migration-coupled DNA damage allows stem cells to reach wound sites

The impact of mechanical stress during cell migration may be a previously unappreciated source of genome instability [1-3], but to what extent this happens in vivo remains unknown. Here we consider an in vivo system where the adult stem cells of planarian flatworms are required to migrate to a distal wound site [4]. We observe a relationship between adult stem cell migration and ongoing DNA damage and repair during tissue regeneration. Migrating planarian stem cells undergo changes in nuclear shape and increased levels of DNA damage. Increased DNA damage levels resolve once stem cells reach the wound site and stop migrating. Stem cells in which DNA damage is induced prior to wounding take longer to initiate migration suggesting migration activity is sensitive to DNA damage. Migrating stem cells populations are more sensitive to further DNA damage than stationary stem cells, providing evidence that levels of migration-coupled-DNA-damage (MCDD) are significant. RNAi mediated knockdown of DNA repair pathway components blocks normal stem cell migration, confirming that DNA repair pathways are required to allow successful migration to a distal wound site. Together these lines of evidence demonstrate that migration leans to DNA damage in vivo and requires DNA repair mechanisms. Our findings reveal that migration of stem cells represents an unappreciated source of damage, that could be a significant source of mutations in animals during development or during long term tissue homeostasis.

developmental biology↗

bioRxiv2018

Sexual antagonism drives the displacement of polymorphism across gene regulatory cascades

Males and females have different reproductive roles and are often subject to contrasting selection pressures. This sexual antagonism can lead, at a given locus, to different alleles being favoured in each sex and, consequently, to genetic variation being maintained in a population. Although the presence of antagonistic polymorphisms has been documented across a range of species, their evolutionary dynamics remain poorly understood. Here we study antagonistic selection on gene expression, which is fundamental to sexual dimorphism, via the evolution of regulatory binding sites. We show that for sites longer than 1 nucleotide, polymorphism is maintained only when intermediate expression levels are deleterious to both sexes. We then show that, in a regulatory cascade, polymorphism tends to become displaced over evolutionary time from the target of antagonistic selection to upstream regulators. Our results have consequences for understanding the evolution of sexual dimorphism, and provide specific empirical predictions for the regulatory architecture of genes under antagonistic selection

evolutionary biology↗

bioRxiv2018

Characterisation of deubiquitylating enzymes in the cellular response to high-LET ionising radiation and complex DNA damage

PurposeIonising radiation, particular high linear energy transfer (LET) radiation, can induce complex DNA damage (CDD) where two or more DNA lesions are induced in close proximity which contributes significantly to the cell killing effects. However knowledge of the enzymes and mechanisms involved in co-ordinating the recognition and processing of CDD in cellular DNA are currently lacking.\n\nMethods and MaterialsAn siRNA screen of deubiquitylation enzymes was conducted in HeLa cells irradiated with high-LET -particles or protons, versus low-LET protons and x-rays, and cell survival monitored by clonogenic assays. Candidates whose depletion led to decreased cell survival specifically in response to high-LET radiation were validated in both HeLa and oropharyngeal squamous cell carcinoma (UMSCC74A) cells, and the association with CDD repair was confirmed by using an enzyme modified neutral comet assay.\n\nResultsDepletion of USP6 decreased cell survival specifically following high-LET -particles and protons, but not by low-LET protons or x-rays. USP6 depletion caused cell cycle arrest and a deficiency in CDD repair mediated through instability of poly(ADP-ribose) polymerase-1 (PARP-1). This phenotype was mimicked using the PARP inhibitor olaparib.\n\nConclusionUSP6 controls cell survival in response to high-LET radiation by stabilising PARP-1 protein levels which is essential for CDD repair. We also describe synergy between CDD induced by high-LET protons and PARP inhibition in effective cancer cell killing.

cancer biology↗

bioRxiv2018

Climate, human influence, and the distribution limits of the invasive European earwig, Forficula auricularia, in Australia

BACKGROUNDBy modelling species-environment relationships of pest species, it is possible to understand potential limits to their distributions when they invade new regions, and their likely continued spread. The European earwig, Forficula auricularia, is a non-native invasive species in Australia that has been in the country for over 170 years. However, in the last few decades it has invaded new areas. Unlike in other countries, F. auricularia is a pest species of grains production in Australia. In this study we detail the Australian distribution of this species, adding new samples focussed around grain growing regions. Using this information we build global species distribution models for F. auricularia to better understand species-environment relationships.\n\nRESULTSOur models indicated that the distribution of F. auricularia is strongly associated with temperate through to semi-arid environments, a high winter rainfall and pronounced temperature seasonality. We identified regions that hold suitable, but as yet vacant, niche space for Australian populations, suggesting further potential for range expansion. Beyond climate, an index describing human influence on the landscape was important to understand the distribution limits of this pest. We identified regions where there was suitable climate space, but which F. auricularia has not occupied likely due to low levels of human impact.\n\nCONCLUSIONModelling the global distribution of a non-native pest species aided understanding of the regional distribution limits within Australia and highlighted the usefulness of human impact measures for modelling globally invasive insect species.

ecology↗

bioRxiv2018

Gene-Based Analysis in HRC Imputed Genome Wide Association Data Identifies Three Novel Genes For Alzheimer’s Disease

A novel POLARIS gene-based analysis approach was employed to compute gene-based polygenic risk score (PRS) for all individuals in the latest HRC imputed GERAD (N cases=3,332 and N controls=9,832) data using the International Genomics of Alzheimers Project summary statistics (N cases=13,676 and N controls=27,322, excluding GERAD subjects) to identify the SNPs and weight their risk alleles for the PRS score. SNPs were assigned to known, protein coding genes using GENCODE (v19). SNPs are assigned using both 1) no window around the gene and 2) a window of 35kb upstream and 10kb downstream to include transcriptional regulatory elements. The overall association of a gene is determined using a logistic regression model, adjusting for population covariates.\n\nThree novel gene-wide significant genes were determined from the POLARIS gene-based analysis using a gene window; PPARGC1A, RORA and ZNF423. The ZNF423 gene resides in an Alzheimers disease (AD)-specific protein network which also includes other AD-related genes. The PPARGC1A gene has been linked to energy metabolism and the generation of amyloid beta plaques and the RORA has strong links with genes which are differentially expressed in the hippocampus. We also demonstrate no enrichment for genes in either loss of function intolerant or conserved noncoding sequence regions.

genetics↗

bioRxiv2018

Proof of concept for quantitative urine NMR metabolomics pipeline for large-scale epidemiology and genetics

BackgroundQuantitative molecular data from urine are rare in epidemiology and genetics. NMR spectroscopy could provide these data in high-throughput, and it has already been applied in epidemiological settings to analyse urine samples. However, quantitative protocols for large-scale applications are not available.\n\nMethodsWe describe in detail how to prepare urine samples and perform NMR experiments to obtain quantitative metabolic information. Semi-automated quantitative lineshape fitting analyses were set up for 43 metabolites and applied to data from various analytical test samples and from 1,004 individuals from a population-based epidemiological cohort. Novel analyses on how urine metabolites associate with quantitative serum NMR metabolomics data (61 metabolic measures; n=995) were performed. In addition, confirmatory genome-wide analyses of urine metabolites were conducted (n=578). The fully automated quantitative regression-based spectral analysis is demonstrated for creatinine and glucose (n= 4,548).\n\nResultsIntra-assay metabolite variations were mostly <5% indicating high robustness and accuracy of the urine NMR spectroscopy methodology per se. Intra-individual metabolite variations were large, ranging from 6% to 194%. However, population-based inter-individual metabolite variations were even larger (from 14% to 1655%), providing a sound base for epidemiological applications. Metabolic associations between urine and serum were found clearly weaker than those within serum and within urine, indicating that urinary metabolomics data provide independent metabolic information. Two previous genome-wide hits for formate and 2-hydroxyisobutyrate were replicated at genome-wide significance.\n\nConclusionsQuantitative urine metabolomics data suggest broad novelty for systems epidemiology. A roadmap for an open access methodology is provided.

epidemiology↗

bioRxiv2017

Effect of vitamin D supplementation on biomarkers of inflammation and immune function: functional genomics analysis of the BEST-D trial

Vitamin D deficiency has been associated with multiple diseases, but the causal relevance and underlying processes are not fully understood. Elucidating the mechanisms of action of drug treatments in humans is challenging, but application of functional genomic approaches in randomised trials may afford an opportunity to systematically assess molecular responses to treatments. In the Biochemical Efficacy and Safety Trial of Vitamin D (BEST-D), 305 community-dwelling individuals aged over 65 years were randomly allocated to treatment with vitamin D34000 IU, 2000 IU or placebo daily for 12 months. Genome-wide genotypes at baseline, and transcriptome and plasma levels of cytokines (IFN-{gamma}, IL-10, IL-8, IL-6 and TNF-) at baseline and after 12 months, were measured. The trial had >90% power to detect a 2-fold change in gene expression. Allocation to vitamin D for 12-months was associated with 2-fold higher plasma levels of 25-hydroxy-vitamin D (25[OH]D), but had no significant effect on whole-blood gene expression (FDR <5%) or on plasma levels of cytokines compared with placebo. In pre-specified analysis, rs7041 (intron variant, GC) had a significant effect on circulating levels of 25(OH)D in the low dose but not on the placebo or high dose vitamin D regimen. A gene expression quantitative trait locus analysis (eQTL) demonstrated evidence of 31,568 cis-eQTLs (unique SNP-probe pairs) among individuals at baseline and 34,254 after supplementation for 12 months (any dose), but had no significant effect on cis-eQTLs specific to vitamin D supplementation. The trial demonstrates the feasibility of application of functional genomics approaches in randomised trials to assess the effects of vitamin D on immune function.\n\nOne sentence summarySupplementation with high-dose vitamin D in older people for 12 months in a randomised, placebo-controlled trial had no significant effect on gene expression or on plasma concentrations of cytokines.\n\nTrial registrationSRCTN registry (Number 07034656) and the European Clinical Trials Database (EudraCT Number 2011-005763-24).\n\nFundingMedical Research Council, British Heart Foundation, Wellcome Trust, European Research Council and Clinical Trial Service Unit, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom\n\nCopyrightOpen access article under the terms of CC BY.

clinical trials↗

bioRxiv2016

A shielded irradiation assay to investigate mechanisms of in vivo stem cell migration in planarians

Migration of stem cells underpins the physiology of metazoan animals. For tissues to be maintained, stem cells and their progeny must migrate and differentiate in the correct positions. This need is even more acute after tissue damage by wounding or pathogenic infections. Inappropriate migration also underpins the formation of metastasis. Despite this, few mechanistic studies address stem cell migration during repair or homeostasis in adult tissues. Here, we present a shielded X-ray irradiation assay that allows us to follow stem cell migration in the planarians. We demonstrate that we can use this system to study the molecular control of stem cell migration and show that snail and zeb-1 EMT transcription factors homologs are necessary for cell migration to wound sites and for the establishment of migratory cell morphology. Our work establishes planarians as a suitable model for further in depth study of the processes controlling stem cell migration in vivo.

developmental biology↗