Biology subjects

Armstrong, R.

Publications and source records attributed to Armstrong, R..

12 recordsLinked to original sources

bioRxiv2026

Mutant ASXL1 Drives Transcriptional Activation and Repression in Human Hematopoiesis

Mutations in the epigenetic regulator ASXL1 are common in myeloid malignancies and portend a near-universally poor prognosis. While multiple mechanisms for mutant ASXL1-dependent oncogenesis have been proposed, none have been functionally validated in the context of the human hematopoietic stem cell, where these mutations almost certainly arise. Here, we extensively characterized a CRISPR-engineered human hematopoietic stem and progenitor cell model of ASXL1 mutations. In this context, mutant ASXL1 expression decreases differentiation, increases clonogenicity in serial replating experiments, and improves engraftment in immunodeficient mice. We also show that endogenous truncating mutations in ASXL1 drive protein stabilization and confirm that mutant ASXL1 is resistant to proteasomal degradation. At the transcriptional level, these phenotypes are driven by significant repression of the stress-response genes and by increased expression of bromodomain and extra-terminal family protein targets. Using protein-interaction screens, genomic and functional approaches, we link the positive transcriptional changes in ASXL1-mutant cells to BRD4-dependent RNA polymerase II pause release and identify a mechanism for transcriptional repression via a previously uncharacterized interaction with the transcription factor MECOM. Finally, we demonstrate that ASXL1-mutant AML exhibits increased MECOM activity consistent with our gene-editing models. Collectively, these studies highlight a highly reproducible model of mutant ASXL1 in the appropriate cell context. Further, they are the first to functionally describe the mutant ASXL1 interactome in the context of the human HSC, identifying new dependencies with therapeutic potential.

cancer biology↗

bioRxiv2025

Early intervention with a PACAP lactoside following repetitive mild traumatic brain injury prevents persistent LHb hyperactivity and motivational deficits in male mice

Mild traumatic brain injury (mTBI) often leads to long-lasting mood disorders and motivational deficits, significantly decreasing quality of life. The neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) has known neuroprotective effects and is often deficient in neurological conditions, but its role in preventing mTBI's long-term effects on mood circuits remains unclear. Our previous studies of repetitive closed-head mTBI in murine models found that the lateral habenula (LHb) is a key area for post-injury impairments. These impairments are characterized by mTBI-induced LHb hyperactivity and mood-related behavioral deficits. Here we investigated if a novel PACAP type I receptor (PAC1R) agonist, TES2320, could prevent or treat these long-term mTBI effects. The drug is based on a truncated glycoside analogue of PACAP that is stable and brain penetrant. Using RNAscope, we first found that mTBI caused a persistent and widespread reduction in PACAP mRNA within the LHb, suggesting a possible mTBI-related PACAP signaling deficiency in LHb circuits. We then used two intervention strategies in young adult male mice: an early intervention administered immediately after injury and a late intervention given as a single injection one-month post-injury. One month after injury, we measured LHb activity and self-care grooming motivation. Both early and late PAC1 agonist interventions almost completely normalized the mTBI-induced increases in LHb spontaneous tonic activity and hyperexcitability. However, only the early intervention improved the delayed initiation of grooming seen in mTBI mice. Unfortunately, a single late PAC1R agonist injection not only failed to reverse the grooming delay, but also significantly reduced total grooming behavior 24 hours after treatment. This finding points to a potential behavioral side effect of late PAC1R agonist administration on grooming. Overall, our findings confirm that an early PAC1R agonist intervention effectively prevents mTBI-induced LHb hyperactivity and associated motivational deficits, likely by restoring the persistent PACAP signaling deficiency in the LHb and its related circuits. This preclinical study provides strong evidence that novel PAC1R agonists could be a valuable preventive therapy for mTBI-related depression and anti-reward circuit dysfunction.

neuroscience↗

bioRxiv2025

Lipid Tail Length Determines Nano-Bio Interactions of Peptide Amphiphile Nanostructures

Understanding the interactions of nanomaterials with biological systems is essential to designing effective nanomedicines. However, most of our understanding originates from studies with solid nanoparticles, and nano-bio interactions of self-assembled nanomaterials have remained largely unexplored. To address this knowledge gap, we develop a series of self-assembling peptide amphiphiles (PAs) with different lipid modifications and investigate their interactions with biological systems. We find that PA nanostructures rapidly disassemble and reassemble with albumin and lipoproteins in blood plasma. While PAs with shorter lipid tails mainly assemble with albumin, increasing lipid length shifts binding to lipoproteins. All PAs show strong tumor accumulation in 4T1 tumor-bearing mice with tumor to liver ratios of [~]3-6. Overall, albumin-binding improves blood circulation and tumor accumulation compared to lipoprotein-binding, but also increases off-target accumulation. This study shows that the biointeractions of self-assembled nanomaterials can be controlled through molecular design, which may lead to the development of effective nanomedicines.

bioengineering↗

bioRxiv2025

Serotonin signaling modulates growth and motility in juvenile Fasciola hepatica

Fasciola hepatica causes fasciolosis, a parasitic disease that poses significant animal and human health challenges. Control relies on flukicides, most of which are adulticides, with only triclabendazole effective against the pathogenic migratory juvenile. Classical neurotransmitter pathways are widely targeted by anthelmintics yet remain underexplored for flukicide development. Here we explore the importance of serotonin (5-HT) signaling in juvenile fluke. In silico analyses confirmed all F. hepatica life stages express a complete 5-HT signaling pathway encompassing genes encoding proteins for 5-HT synthesis, transport, and reuptake, as well as five putative 5-HT G protein-coupled receptors (GPCRs). Homology and binding motif analyses supported the presence of two 5-HT1 (Fh5HT1A, Fh5HT1B) and three 5-HT7 (Fh5HT7A, -7B, -7C) GPCRs. Immunocytochemistry and in situ hybridization revealed widespread neuronal expression of 5-HT, its synthetic enzyme tryptophan hydroxylase (FhTPH), and the GPCR Fh5HT7C. 5-HT addition stimulated juvenile fluke motility; consistent with this observation, serotonin reuptake inhibition, which causes 5-HT persistence at synaptic junctions, also enhanced juvenile movement. Silencing of FhTPH, a key enzyme in 5-HT synthesis, blunted juvenile motility, a phenotype reversed by the addition of 5-HT. Silencing the fluke vesicular monoamine transporter (FhVMAT), which packages 5-HT into synaptic vesicles, reduced juvenile motility, whilst silencing the 5-HT reuptake transporter (FhSERT) which recycles synaptic 5-HT increased juvenile motility and growth, consistent with 5-HT accumulation enhancing effects. Whilst combinatorial silencing of Fh5HT1 receptors reduced fluke motility, silencing Fh5HT7 receptors led to a greater reduction in motility. Exogenous addition of 5-HT partially rescued motility deficits of juveniles with silenced Fh5HT1 receptors, but 5-HT excitation was abolished in Fh5HT7-RNAi juveniles, exposing their importance to fluke motility. Notably, sustained 5-HT exposure promoted juvenile growth, but these effects were not blunted by receptor-RNAi. The findings emphasize a central role of serotonin signaling in both juvenile motility and growth, exposing novel aspects of receptor function and encouraging therapeutic exploitation for liver fluke control. Author SummaryThe liver fluke, Fasciola hepatica, causes fasciolosis, a neglected tropical disease that poses a significant burden on human and animal health. There is no vaccine for fasciolosis and treatment relies on a single drug, triclabendazole, to control the early stages of infection which cause liver pathology whilst migrating through the mammalian host. Single drug reliance has increased the incidence of drug resistance in both human and animal populations, such that there is a pressing need for the characterization of novel drug targets and development of new anthelmintics targeting liver fluke. The focus of this research is to examine the role of the serotonin signaling system of liver fluke, bridging a gap in knowledge to enable the exploitation of this signaling pathway for flatworm drug development. Here, bioinformatic analysis has characterized the pathway components and receptors in multiple clinically relevant flatworm parasite species. Chemical and functional genomic methods have been used to prove the integral function of serotonin in liver fluke biology, regulating motility and growth, both essential for parasite infection and survival. This work provides data that help validate the serotonergic system of liver fluke as a potential target for future anthelmintic development.

molecular biology↗

bioRxiv2025

A Trypanosome Trifecta: an independently tunable triple inducer system for genetic studies in Trypanosoma brucei.

Trypanosoma brucei is a model unicellular parasite for cellular and molecular genetic studies, but tools for more multiplexed experiments are limited. Tetracycline (Tet)-inducible gene regulation has been a long-standing and effective approach for overexpression, RNAi and genome wide screens. The single inducer Tet-On system has been foundational for studying essential genes that are required for biological processes and identifying potential drug targets. To achieve greater flexibility in experimental design, we capitalized upon previously described dual inducer systems that combined vanillic acid (Van) or cumate (Cym) with Tet as inducers. Here we report the development of a triple inducer system combining Cym, Van and Tet repressor elements to selectively regulate the expression of three genetic elements within a single cell line called PHITER. As proof of principle to demonstrate independent control, we adapted the previously characterized Van/Tet dual inducer RNAi complementation cell line, IBCompVaT for additional Cym inducible expression of an eGFP reporter. We provide evidence that each of the inducer elements operate independently with no evidence of leaky expression. In this system, Cym induction is specific and tunable. Additionally, simultaneous triple induction for POLIB RNAi complementation with wildtype POLIB and eGFP expression phenocopied the near complete rescue of POLIB RNAi previously reported. This system enables the study of complex and pleiotropic phenotypes through more sophisticated experimental design.

microbiology↗

bioRxiv2025

Polo-like kinase 1 regulates growth in juvenile Fasciola hepatica

Fasciola sp. (liver fluke) are parasitic flatworms that impose a significant burden on the agri-food industry and human health. Immature worms can cause severe damage to the liver as they migrate towards the bile ducts, and yet there is only a single drug to treat this pathogenic life stage, driving the need to identify targets for novel flukicides. Given their crucial role in the growth/development of immature Fasciola hepatica, neoblast-like stem cells are an attractive source of new flukicide targets. Kinases are a hugely diverse group of phosphorylating enzymes with key roles in almost all cellular processes. Kinase dysregulation can result in the development of cancerous cells/tissues, linking many to cell cycle-associated proliferation and growth. Here, we annotate the F. hepatica kinome, identifying 271 putative protein kinases, representing around 1.6% of predicted F. hepatica protein-coding genes with family proportions similar to those of other parasitic flatworms. Many of these kinases, such as polo-like kinase 1 (fhplk1), are upregulated in immature worms undergoing rapid growth and development, a process underpinned by the proliferation of neoblast-like stem cells. RNA interference (RNAi)-mediated silencing of fhplk1 in juvenile liver fluke reduced growth and cell proliferation, suggesting a conserved role within the cell-cycle; the cessation of stem cell proliferation persisted for at least a week following fhplk1-RNAi. A PLK inhibitor (BI 2536) was shown to phenocopy the fhplk1-RNAi phenotype in a dose-dependent manner, supporting the feasibility of targeting F. hepatica neoblast-like cells through kinase inhibitors. Transcriptomic analysis of fhplk1-RNAi juveniles revealed 946 downregulated genes, principally associated with the cell cycle or ribosomes. Over 80 of these downregulated genes were also downregulated following juvenile F. hepatica irradiation, supporting roles for these kinases in neoblast-like stem cells, and marking them as putative targets for control. Among the 1244 upregulated genes in fhplk1-RNAi juvenile worms were many neurotransmitters, receptors and ion channels, exposing the apparent upregulation of diverse inter-cellular signalling systems. While many neurotransmitter pathways promote proliferation in mammalian systems the interaction between neoblast-like stem cells and neuronal signalling in parasitic flatworms remains elusive. Here, the transcriptomic response of fhplk1-RNAi juveniles supports a link between neoblast-like stem cell driven growth/development and neuronal signalling. Author SummaryThe liver fluke is a parasitic flatworm which causes disease in livestock and humans around the world. While establishing the infection, immature liver fluke migrate through the host liver causing significant damage. Unfortunately, only one drug is currently recommended for treatment of these immature worms, though resistance to this drug is now widespread and exposes the pressing need to develop novel drugs. As worms migrate through the liver, they undergo growth and development which is facilitated by proliferating stem cells. These neoblast-like cells are akin to stem cells seen in other organisms, and as such are responsible for new tissue growth. Many stem cells express kinases, a large family of enzymes that control many cellular processes. In this study we identified all the potential kinases in the liver fluke, including those that may function in neoblast-like stem cells. One of these kinases, polo-like kinase 1 (PLK1), has been linked to cancer development in humans. We used reverse genetics to silence this gene, allowing us to understand its function. Silencing PLK1 reduced worm growth and stopped neoblast-like cell proliferation, confirming that it has an important role in growth and cell division. Also, we showed that a PLK1 inhibitor, developed for cancer treatments, reduced growth and neoblast-like cell activity, illustrating the potential for targeting liver fluke kinases associated with neoblast-like cells with drugs, providing new routes to drug development. We then carried out RNA sequencing of worms after PLK1 was silenced to show the effects of neoblast-like cell loss on the expression of other genes. We found a decrease in the expression of genes that regulate cell division, but an increase in the expression of genes related to inter-cell signalling, including neuronal genes. This supports evidence for interactions between the nervous system and neoblast-like cells which could be exploited in future drug discovery.

molecular biology↗

bioRxiv2025

An independently tunable dual control system for RNAi complementation in Trypanosoma brucei

Trypanosoma brucei is a tractable protist parasite for which many genetic tools have been developed to study novel biology. A striking feature of T. brucei is the catenated mitochondrial DNA network called the kinetoplast DNA (kDNA) that is essential for parasite survival and life cycle completion. Maintenance of kDNA requires three independently essential paralogs that have homology to bacterial DNA polymerase I (POLIB, POLIC and POLID). We previously demonstrated that POLIB has a divergent domain architecture that displayed enzymatic properties atypical for replicative DNA polymerases. To evaluate the functional domains required for kDNA replication in vivo, we pursued an RNAi complementation approach based on the widely used tetracycline (Tet) single inducer system. Tet induction of RNAi and complementation with wildtype POLIB (POLIBWT) resulted in a 93% knockdown of endogenous POLIB mRNA but insufficient ectopic POLIBWT expression. This incomplete rescue emphasized the need for a more versatile induction system that will allow independent, tunable, and temporal regulation of gene expression. Hence, we adapted a dual control vanillic acid (Van)-Tet system that can independently control gene expression for robust RNAi complementation. Dual induction with Van and Tet (RNAi + Overexpression) resulted in 91% endogenous POLIB knockdown accompanied by robust and sustained ectopic expression of POLIBWT, and a near complete rescue of the POLIB RNAi defects. To more precisely quantify changes in kDNA size during RNAi, we also developed a semi-automated 3D image analysis tool to measure kDNA volume. Here we provide proof of principle for a dual inducer system that allows more flexible control of gene expression to perform RNAi and overexpression independently or concurrently within a single cell line. This system overcomes limitations of the single inducer system and can be valuable for elegant mechanistic studies in the field.

molecular biology↗

bioRxiv2024

Wnt/β-catenin signalling underpins juvenile Fasciola hepatica growth and development

Infection by the liver fluke, Fasciola hepatica, places a substantial burden on the global agri-food industry and poses a significant threat to human health in endemic regions. Widespread resistance to a limited arsenal of chemotherapeutics, including the frontline flukicide triclabendazole (TCBZ), renders F. hepatica control unsustainable and accentuates the need for novel therapeutic target discovery. A key facet of F. hepatica biology is a population of specialised stem cells which drive growth and development - their dysregulation is hypothesised to represent an appealing avenue for control. The exploitation of this system as a therapeutic target is impeded by a lack of understanding of the molecular mechanisms underpinning F. hepatica growth and development. Wnt signalling pathways govern a myriad of stem cell processes during embryogenesis and drive tumorigenesis in adult tissues. Here, we identify five putative Wnt ligands and five Frizzled receptors in liver fluke transcriptomic datasets and find that Wnt/{beta}-catenin signalling is most active in juveniles, the most pathogenic life stage. FISH-mediated transcript localisation revealed partitioning of the five Wnt ligands, with each displaying a distinct expression pattern, consistent with each Wnt regulating the development of different cell/tissue types. The silencing of each individual Wnt or Frizzled gene yielded significant reductions in juvenile worm growth and, in select cases, blunted the proliferation of neoblast-like cells. Notably, silencing FhCTNNB1, the key effector of the Wnt/{beta}-catenin signal cascade led to aberrant development of the neuromuscular system which ultimately proved fatal - the first report of a lethal RNAi-induced phenotype in F. hepatica. The absence of any discernible phenotypes following the silencing of the inhibitory Wnt/{beta}-catenin destruction complex components is consistent with low destruction complex activity in rapidly developing juvenile worms, corroborates transcriptomic expression profiles and underscores the importance of Wnt signalling as a key molecular driver of growth and development in early stage juvenile fluke. The pharmacological inhibition of Wnt/{beta}-catenin signalling using commercially available inhibitors phenocopied RNAi results and provides impetus for drug repurposing. Taken together, these data functionally and chemically validate the targeting of Wnt signalling as a novel strategy to undermine the pathogenicity of juvenile F. hepatica. AUTHOR SUMMARYThe liver fluke, Fasciola hepatica significantly undermines the health and welfare of livestock worldwide and causes fascioliasis, a neglected tropical disease of humans. The most damaging stage of liver fluke infection is caused by the migration of juvenile worms within the liver tissue. Of all drugs approved for liver fluke treatment, just one, triclabendazole (TCBZ), is active on this pathogenic juvenile stage. TCBZ resistance is now widespread rendering liver fluke control unsustainable. This highlights the need for novel drug target identification and validation. A key aspect of juvenile worm biology is their ability to rapidly grow and develop, processes driven by a population of specialised stem cells. As such, the dysregulation of stem cells represents an attractive avenue for liver fluke control. One molecular pathway known to regulate stem cell dynamics in higher organisms is the Wnt signalling pathway. Bioinformatic searches of gene sequence datasets identified all major signalling components of both canonical and non-canonical Wnt pathways in F. hepatica. The localisation of FhWnt pathway components revealed remarkably distinct and widespread expression patterns throughout the F. hepatica body. Gene silencing of putative FhWnt pathway components revealed that those involved in the Wnt/{beta}-catenin signal cascade are fundamental to juvenile growth and, in some cases, stem-like cell proliferation. The silencing of liver fluke {beta}-catenin led to aberrant neuromuscular development and proved lethal to juvenile fluke. Biweekly exposures to commercially available Wnt pathway inhibitory compounds phenocopied the delayed development observed in the gene silencing experiments. These data suggest that FhWnt pathway components represent attractive targets for the development of novel flukicides or indeed, the repurposing of existing Wnt antagonists for parasite control.

developmental biology↗

bioRxiv2023

Neoblast-like Stem Cells of Fasciola hepatica

The common liver fluke (Fasciola hepatica) causes the disease fasciolosis, which results in considerable losses within the global agri-food industry. There is a shortfall in the drugs that are effective against both the adult and juvenile life stages within the mammalian host, such that new drug targets are needed. Over the last decade the stem cells of parasitic flatworms have emerged as reservoirs of putative novel targets due to their role in development and homeostasis, including at host-parasite interfaces. Here, we investigate and characterise the proliferating cells that underpin development in F. hepatica. We provide evidence that these cells are capable of self-renewal, differentiation, and are sensitive to ionising radiation - all attributes of neoblasts in other flatworms. Changes in cell proliferation were also noted during the early stages of in vitro juvenile growth/development (around four to seven days post excystment), which coincided with a marked reduction in the nuclear area of proliferating cells. Furthermore, we generated transcriptomes from worms following irradiation-based ablation of neoblasts, identifying 124 significantly downregulated transcripts, including known stem cell markers such as fgfrA and plk1. Sixty-eight of these had homologues associated with neoblast-like cells in Schistosoma mansoni. Finally, RNA interference mediated knockdown of histone h2b (a marker of proliferating cells), ablated neoblast-like cells and impaired worm development in vitro. In summary, this work demonstrates that the proliferating cells of F. hepatica are equivalent to neoblasts of other flatworm species and demonstrate that they may serve as attractive targets for novel anthelmintics. Author SummaryLiver fluke are parasitic worms that infect both livestock and humans worldwide, threatening food security and human health. Treatments against this disease-causing parasite are limited, and growing resistance to drugs is undermining the effectiveness of control strategies. Since drugs represent the only viable control option, it is crucial that new drugs are discovered through the identification and validation of new drug targets. Stem cells play important roles in the normal growth and repair processes of many organisms, but when these cells become dysregulated through mutation, they can drive the development of cancers. Stem cells of liver fluke may be attractive novel drug targets as disruption would affect worm survival and/or development within their host. In this research we describe the characteristics of liver fluke stem cells, such as their sensitivity to radiation and their ability to develop into new cell types (key stem cell features). We used radiation in combination with RNA sequencing to identify genes associated with the liver fluke stem cells. Finally, we used reverse genetics to reduce the expression of a gene associated with stem cells, which led to the loss of stem cells and reduced worm growth/development. These data provide evidence to support the exploitation of stem cells as a source of novel drug targets for liver fluke control.

molecular biology↗

bioRxiv2022

Microphysiological vascular malformation model reveals a role of dysregulated Rac1 and mTORC1/2 in lesion formation.

Somatic activating mutations of PIK3CA are associated with the development of vascular malformations (VMs). Here, we describe a microfluidic model of PIK3CA-driven VMs consisting of human umbilical vein endothelial cells (HUVECs) expressing PIK3CA activating mutations embedded in 3D hydrogels. We observed enlarged and irregular vessel phenotypes, consistent with clinical signatures and concomitant with PI3K-driven upregulation of Rac1/PAK, MEK/ERK, and mTORC1/2 signaling. We observed differential effects between Alpelisib, a PIK3CA inhibitor, and Rapamycin, an mTORC1 inhibitor, in mitigating matrix degradation and vascular network topology. While both drugs are effective in preventing vessel enlargement, Alpelisib suppressed mTORC2-dependent AKT1 phosphorylation and MEK/ERK signaling. Rapamycin failed to reduce MEK/ERK and mTORC2 activity and resulted in vascular hyperbranching, while inhibiting PAK, MEK1/2, and mTORC1/2 signaling mitigates abnormal growth and vascular dilation. Collectively, these findings establish an in vitro platform for modeling VMs and confirm a role of dysregulated Rac1/PAK and mTORC1/2 signaling in PIK3CA-driven VMs.

bioengineering↗

bioRxiv2022

Transcriptomic analysis reveals a role for the nervous system in regulating growth and development of Fasciola hepatica juveniles

Fasciola spp. liver fluke have significant impacts in veterinary and human medicine. The absence of a vaccine and increasing anthelmintic resistance threaten sustainable control and underscore the need for novel flukicides. Functional genomic approaches underpinned by in vitro culture of juvenile Fasciola hepatica facilitate control target validation in the most pathogenic life stage. Comparative transcriptomics of in vitro and in vivo maintained 21 day old F. hepatica finds that 86% of genes are expressed at similar levels across maintenance treatments suggesting commonality in core biological functioning within these juveniles. Phenotypic comparisons revealed higher cell proliferation and growth rates in the in vivo juveniles compared to their in vitro counterparts. These phenotypic differences were consistent with the upregulation of neoblast-like stem cell and cell-cycle associated genes in in vivo maintained worms. The more rapid growth/development of in vivo juveniles was further evidenced by a switch in cathepsin protease expression profiles, dominated by cathepsin B in in vitro juveniles and then by cathepsin L in in vivo juveniles. Coincident with more rapid growth/development was the marked downregulation of both classical and peptidergic neuronal signalling components in in vivo maintained juveniles, supporting a role for the nervous system in regulating liver fluke growth and development. Differences in the miRNA complements of in vivo and in vitro juveniles identified 31 differentially expressed miRNAs, notably fhe-let-7a-5p, fhe-mir-124-3p and, miRNAs predicted to target Wnt-signalling, supporting a key role for miRNAs in driving the growth/developmental differences in the in vitro and in vivo maintained juvenile liver fluke. Widespread differences in the expression of neuronal genes in juvenile fluke grown in vitro and in vivo expose significant interplay between neuronal signalling and the rate of growth/development, encouraging consideration of neuronal targets in efforts to dysregulate growth/development for parasite control. Author SummaryParasitic worms are notoriously difficult to study outside of a host organism. However, recent developments in culture methods for Fasciola hepatica liver fluke juveniles support growth and development of these parasites in the laboratory (in vitro) towards adult parasites. Having the ability to grow pathogenic juvenile stages in vitro enables functional studies to validate potential drug and vaccine targets. However, comparison of in vitro grown juveniles to juveniles retrieved from infected hosts (in vivo) shows considerable size differences suggesting at least some differences in biology that could undermine the relevance of data generated from in vitro maintained parasites. This study examines gene expression differences between in vitro and in vivo maintained F. hepatica juveniles via transcriptomic analysis to identify similarities and differences in their biology which may help explain differences in the rate of growth and development. 86% of genes were shown to be expressed at similar levels across treatment groups suggesting a high level of biological similarity between in vitro and in vivo juveniles. However, the genes that are expressed differently between these juveniles will help improve current culture methods and provide a new group of potential drug targets that impact on juvenile growth and development.

molecular biology↗

bioRxiv2017

African Nonhuman Primates Are Infected With The Yaws Bacterium Treponema pallidum subsp. pertenue

Treponema pallidum subsp. pertenue (TPE) is the causative agent of yaws. The disease was subject to global eradication efforts in the mid 20th century but reemerged in West Africa, Southern Asia, and the Pacific region. Despite its importance for eradication, detailed data on possible nonhuman disease reservoirs are missing. A number of African nonhuman primates (NHPs) have been reported to show skin ulcerations suggestive of treponemal infection in humans. Furthermore antibodies against Treponema pallidum (TP) have been repeatedly detected in wild NHP populations. While genetic studies confirmed that NHPs are infected with TP strains, subspecies identification was only possible once for a strain isolated in 1966, pinpointing the involvement of TPE. We therefore collected a number of recently isolated simian TP strains and determined eight whole genome sequences using hybridization capture or long-range PCR combined with next-generation sequencing. These new genomes were compared with those of known human TP isolates. Our results show that naturally occurring simian TP strains circulating in three African NHP species all cluster with human TPE strains and show the same genomic structure as human TPE strains. These data indicate that humans are not the exclusive host for the yaws bacterium and that a One Health approach is required to achieve sustainable eradication of human yaws.

microbiology↗