Biology subjects

Shaw, S.

Publications and source records attributed to Shaw, S..

At least 19 recordsLinked to original sources

bioRxiv2026

A defined multi-kingdom microbial consortium naturalizes the immune system of laboratory mice

Dirty mice experiments suggest that laboratory mice fail to model certain human immune responses due to their limited microbial exposure. The identity, nature, and number of microbes required to normalize the immune system are unknown. Through systematic screening, we uncovered unexpected cross-kingdom microbial interactions and identified four enteric microbes spanning viruses, fungi, and protists sufficient to reproduce key immunological features of pet store mice and adult humans. This consortium also altered cancer outcomes, shifting tumorigenesis toward the anatomical pattern of human familial adenomatous polyposis in ApcMin/+ mice and recapitulating the imperfect response of many patients to chimeric antigen receptor (CAR) T cell therapy. Thus, surprisingly few microbes can profoundly reshape immune states and disease responses, providing a tractable approach to naturalize laboratory mouse immunity.

immunology↗

bioRxiv2026

Cryptic Genes as Building Blocks of Antimicrobial Resistance: Evidence from a Novel Marine Imipenem-Hydrolyzing Metallo-β-Lactamase

The emergence of antimicrobial resistant pathogens has led to increase in mortality rate, longer hospital stays, and need for complex and expensive treatment regimens. However, it is not very clear from where does the bacteria get the building blocks to develop resistance to these synthetic antimicrobial agents which have been integral part of modern medicine. One hypothesis is that non-coding cryptic genes without any vital function or positive contribution to fitness act as versatile endogenous genetic repertoires that help in bacterial adaptation and evolution of new phenotypes when conditions change. This study reports the presence of putative cryptic metallo beta lactamase gene in the marine bacterium Cytobacillus oceanisediminis isolated from the Gulf of Mannar, India. Using in silico, in vitro and in vivo assay, we demonstrate that putative cryptic metallo beta lactamase encodes an enzyme that can cleave only imipenem, has two characteristic domains: HXHXDH and TPGH, but does not share homology with the other reported Metallo-beta-Lactamase genes. The findings underscore the importance for comprehensive screening of putative cryptic antimicrobial resistance genes to fully address and mitigate the challenges posed by antimicrobial resistance.

microbiology↗

bioRxiv2026

Ablation of a maternal Cryptosporidium mRNA-binding protein results in sterile sporozoites

Infection with Cryptosporidium is a leading cause of diarrheal disease and early childhood mortality. This apicomplexan parasite undergoes asexual and sexual replication within the same host and recent studies have shown an intrinsic developmental program of obligate transition to male and female gametes and sex. While factors were identified that control male fate and development, how female gene expression is orchestrated remains largely unknown. Here we use the Cryptosporidium Single Cell Atlas to discover an RNA binding protein (F-RBP) as one of the earliest markers of female identity. Reporter parasites engineered based on this gene allowed us to calibrate transcriptional pseudotime against the real time of female development revealing a significant window of transcriptional fate ambiguity. While F-RBP is an early transcript, the protein persists throughout female development and into the zygote. Conditional ablation of the F-RBP gene showed it to be dispensable for sex determination and early female development in vitro. However, the gene is essential in vivo and its loss results in rapid cure. Cell biological experiments link this loss to the production of sterile oocysts which release sporozoites incapable of host cell invasion. F-RBP binds transcripts highly expressed in the female gamete enriched for a YBOX primary sequence motif and forms mRNA protein complexes in late females akin to processing or P bodies. We propose F-RBPs essential role to be in the regulation of long-term homeostasis of maternally inherited RNA required for sporozoite infectivity.

microbiology↗

bioRxiv2026

Signaling input from the polar flagellum uncouples quorum sensing from cell-density regulation in Vibrio species

Quorum sensing (QS) is traditionally recognized as a signaling mechanism that monitors cell density to coordinate bacterial group behaviors. Although the architecture of many QS pathways and their dependence on cell density are well established, the impact from other physiological cues on QS response is largely unclear. We demonstrate here that flagellar integrity profoundly influences QS responses across multiple Vibrio species. Systematic disruption of flagellar components in Vibrio cholerae revealed that loss of the hook cap protein FlgD induces QS sRNAs Qrr1-4 production independent of cell density and the canonical QS regulator LuxO. This bypass mechanism also overrides normal cell density-dependent regulation of several QS-controlled phenotypes. Notably, {Delta}flgD mutation restores intestinal colonization of {Delta}luxO mutants in an infant mouse model, indicating that flagellar defects reshape V. cholerae QS during infection. This bypass mechanism is evolutionarily conserved as {Delta}flgD mutation induced LuxO-independent qrr expression in multiple Vibrio species. The FlrBC two-component system, essential for flagellar gene expression, is required for the activation of qrr expression in {Delta}flgD mutants. FlgD specifically interacts with the FlrB histidine kinase but not the FlrC response regulator, and a hyperactive FlrC variant is sufficient to drive qrr expression even in cells with FlgD. These findings suggest that not only FlrBC senses cytoplasmic FlgD levels to monitor flagellar completeness to direct flagellar gene expression, this signaling system also functions as a link to bypass the canonical cell-density control of QS by integrating cellular structural information to coordinate group behaviors.

microbiology↗

bioRxiv2026

A comprehensive CRISPR screen of the Drosophila glutamate receptome reveals Ekar as a selective regulator of presynaptic homeostatic plasticity

Homeostatic mechanisms protect synapses from destabilizing challenges throughout an organisms lifespan, ensuring stable yet flexible neural network activity. To delineate the molecular basis of presynaptic homeostatic potentiation (PHP), we conducted a comprehensive, in vivo CRISPR/Cas9-based screen of all 16 glutamate receptor (GluR) genes encoded in the Drosophila genome. We first generated a complete expression atlas across larval and adult stages, identifying nine GluRs expressed in presynaptic motor neurons. We then generated null mutants for all 16 GluRs and screened them at the larval neuromuscular junction. While the loss of any single presynaptic GluR did not affect baseline synaptic growth or neurotransmission, our screen revealed a selective and critical requirement for the kainate receptor subunit ekar in the expression of chronic PHP. Further genetic analysis indicates that Ekar functions coordinately with the kainate receptor subunits KaiRID and Ukar within a shared pathway to promote this plasticity. Mechanistically, Ekar acts downstream of active zone remodeling to drive the homeostatic enhancement of presynaptic Ca2+ influx, which is the defining feature of chronic PHP. Together, this genome-wide analysis establishes a definitive functional atlas for the Drosophila glutamate receptome and highlights a specialized, essential role for Ekar in stabilizing long-term synaptic homeostasis.

neuroscience↗

bioRxiv2025

epsSMASH uncovers exopolysaccharide biosynthetic gene clusters in environmental and human microbiomes

Biofilms represent the default mode of bacterial life in natural and built environments, with extracellular polysaccharides (exoPS) serving as essential structural and functional components of the biofilm matrix. Despite their importance, exoPS production in these environments is largely unknown. Here we present epsSMASH, a bioinformatic tool and web service for predicting known and novel exoPS biosynthetic gene clusters (BGCs) in bacterial genomes. Benchmarking showed that comprehensive detection of exoPS gene clusters requires highly contiguous high-quality genome assemblies. We applied epsSMASH to high-quality bacterial genome catalogues representing four major ecosystems: Human gut, soil, ocean and activated sludge from wastewater treatment systems. In all catalogues, epsSMASH identified exoPS BGCs in most genomes (52.8-85.4%), with a median of 1-2 exoPS BGCs per genome. The number of exoPS BGC per genome was highly variable, with some taxa containing up to 19 distinct exoPS BGCs. Pel BGCs were abundant in human gut, ocean and activated sludge microbiomes, and were detected in 14 different phyla, making it the most phylogenetically widespread BGC in these environments. The vast majority (62-96%) of detected exoPS BGCs were uncharacterised. By constructing gene cluster families from uncharacterised systems, we identified novel and phylogenetically widespread exoPS BGCs. We investigated a novel exoPS gene cluster from the activated sludge microbiome and showed that it is conserved in most genera within the order Sphingomonadales. Our results highlight the remarkable number of uncharacterised exoPS gene clusters in environmental microbiomes and establish epsSMASH as an effective tool for identifying and classifying novel exoPS systems.

bioinformatics↗

bioRxiv2025

Widespread genomic heterogeneity at the type II NAD(P)H dehydrogenase locus predisposes Cryptosporidium to clofazimine resistance

The parasite Cryptosporidium is a leading cause of life-threatening diarrheal disease, and effective treatment is not available. The discovery of potent anti-Cryptosporidium activity of clofazimine, offered the opportunity to repurpose a drug already used to treat leprosy and tuberculosis. However, clofazimine failed in a human trial, which was attributed to poor bioavailability. Here, we observed differential susceptibility among parasite isolates which we exploit to map the mode of action to type II NADH dehydrogenase (NDH2) in an unbiased genetic cross. Targeted genetic ablation of NDH2 resulted in profound clofazimine resistance, and biochemical studies demonstrated NDH2 mediated electron transfer to clofazimine. Through genomic analyses we uncovered heterogeneity at the NDH2 locus for C. parvum and C. hominis and widespread carriage of a conserved attenuated allele across multiple continents. This heterogeneity allows parasites genomically linked through frequent sexual recombination to adjust to changing NDH2 requirements and predisposes Cryptosporidium to evade clofazimine treatment.

microbiology↗

bioRxiv2025

Genetic crosses reveal genomic loci responsible for virulence in Cryptosporidium parvum infection

The relationship between parasite genotype and pathogenesis is largely unknown for Cryptosporidium, a leading cause of diarrheal disease in children. An array of parasites with similar genomes produces varied disease outcomes in different hosts. Here, we isolate and characterize Cryptosporidium parvum strains that show marked differences in virulence and persistence in mice. Taking advantage of the sexual lifecycle of this eukaryotic pathogen, we use genetic crosses to discover the underlying chromosomal loci. Whole-genome sequencing and bulk segregant analysis of infection selected progeny mapped three loci on chromosomes 2, 6, and 7 associated with the ability to colonize and persist in mice and the positions of drug resistance genes. The chromosome 6 locus encodes the hyper-polymorphic surface glycoprotein GP60. Reverse genetic studies in both parental strains demonstrate that GP60 controls parasite burden and virulence, but not persistence, and reveal the dominance of the less virulent allele, suggesting it restricts virulence.

genetics↗

bioRxiv2024

ActinoMation: a literate programming approach for medium-throughput robotic conjugation of Streptomyces spp.

The genus Streptomyces are valuable producers of antibiotics and other pharmaceutically important bioactive compounds. Advances in molecular engineering tools, such as CRISPR, has provided some access to the metabolic potential of Streptomyces, but efficient genetic engineering of strains is hindered by laborious and slow manual transformation protocols. In this paper, we present a semi-automated medium-throughput workflow for the introduction of recombinant DNA into Streptomyces spp. using the affordable and open-sourced Opentrons (OT-2) robotics platform. To increase the accessibility of the workflow we provide an open-source protocol-creator, ActinoMation. ActinoMation is a literate programming environment using Python in Jupyter Notebook. We validated the method by transforming Streptomyces coelicolor (M1152 and M1146), S. albidoflavus (J1047), and S. venezuelae (DSM40230) with the plasmids pSETGUS and pIJ12551. We demonstrate conjugation efficiencies of 3.33*10-3 for M1152 with pSETGUS and pIJ12551; 2.96*10-3 for M1146 with pSETGUS and pIJ12551; 1.21*10-5 for J1047 with pSETGUS and 4.70*10-4 with pIJ12551, and 4.97*10-2 for DSM40230 with pSETGUS and 6.13*10-2 with pIJ12551 with a false positive rate between 8.33% and 54.54%. Automation of the conjugation workflow improves consistency when handling large sample sizes that facilitates easy reproducibility on a larger scale.

bioengineering↗

bioRxiv2024

Cyclooxygenase-2 disruption predisposes to heart failure with preserved ejection fraction

Heart failure (HF) is one of the most strongly associated adverse cardiovascular events linked to the use of cyclooxygenase (COX)-2 selective and non-selective nonsteroidal anti-inflammatory drug (NSAID). Nevertheless, it remains uncertain whether NSAID exposure is more likely to lead to heart failure with reduced ejection fraction (HFrEF) or preserved ejection fraction (HFpEF). In adult mice, postnatal genetic deletion or pharmacological inhibition of COX-2 did not affect cardiac function. In contrast, aged female inducible COX-2 (iCOX-2) knockout (KO) mice displayed diastolic dysfunction, cardiac hypertrophy, pulmonary congestion, and elevated levels of plasma N-terminal pro B-type natriuretic peptide (BNP) when compared to age- and sex- matched controls, while their ejection fraction (EF) remained preserved ([≥] 50%). No such phenotype was observed in aged male iCox-2 KO mice. Aged female iCox-2 KO mice showed a shift from prostanoid to leukotriene biosynthesis, along with changes in the expression of mitochondrial genes and calcium-handling proteins in the myocardium. The ratio of phospholamban to SERCA2a was increased, indicating an inhibitory effect on SERCA2a activity, which may contribute to impaired myocardial relaxation. In larval zebrafish, COX-2 inhibition by celecoxib caused a modest yet significant reduction in heart rate and diastolic function, while EF was preserved. Additionally, celecoxib increased BNP expression and ventricular calcium transient amplitude. Diabetic patients in the Harvard-Partners electronic medical record exposed to NSAIDs selective for COX-2 inhibition were more strongly associated with an increased risk of HFpEF compared to HFrEF. Collectively, these findings indicate that COX-2 deletion or inhibition does not impair systolic cardiac function but instead leads to an HFpEF phenotype in mice, zebrafish, and humans. An imbalance in calcium handling may mediate the impairment of myocardial relaxation following COX-2 suppression. SummaryGenetic deletion or pharmacological inhibition of COX-2 results in heart failure with preserved ejection fraction across zebrafish, mice, and humans.

pharmacology and toxicology↗

bioRxiv2024

Combining population genomics and transcriptomics to identify signatures of metal tolerance in brown trout inhabiting metal-polluted rivers

Industrial pollution is a major driver of ecosystem degradation, but it can also act as a driver of contemporary evolution. As a result of intense mining activity during the Industrial Revolution, several rivers across the southwest of England are polluted with high concentrations of metals. Despite the documented negative impacts of ongoing metal pollution, brown trout (Salmo trutta L.) survive and thrive in many of these metal-impacted rivers. We used population genomics, transcriptomics, and metal burdens to investigate the genomic and transcriptomic signatures of potential metal tolerance. RADseq analysis of six populations (originating from three metal-impacted and three control rivers) revealed strong genetic substructuring between impacted and control populations. We identified selection signatures at 122 loci, including genes related to metal homeostasis and oxidative stress. Trout sampled from metal-impacted rivers exhibited significantly higher tissue concentrations of cadmium, copper, nickel, and zinc, which remained elevated after 11 days in metal-free water. After depuration, we used RNAseq to quantify gene expression differences between metal-impacted and control trout, identifying 2,042 differentially expressed genes (DEGs) in the gill, and 311 DEGs in the liver. Transcriptomic signatures in the gill were enriched for genes involved in ion transport processes, metal homeostasis, oxidative stress, hypoxia and response to xenobiotics. Our findings reveal shared genomic and transcriptomic pathways involved in detoxification, oxidative stress responses, and ion regulation. Overall, our results demonstrate the diverse effects of metal pollution in shaping both neutral and adaptive genetic variation, whilst also highlighting the potential role of constitutive gene expression in promoting metal tolerance.

evolutionary biology↗

bioRxiv2024

Identification of Small Molecule Inhibitors of PPM1D Using a Novel Drug Discovery Platform

Protein phosphatase, Mg2+/Mn2+ dependent 1D (PPM1D), is a serine/threonine phosphatase that is recurrently activated in cancer, regulates the DNA damage response (DDR), and suppresses the activation of p53. Consistent with its oncogenic properties, genetic loss or pharmacologic inhibition of PPM1D impairs tumor growth and sensitizes cancer cells to cytotoxic therapies in a wide range of preclinical models. Given the therapeutic potential of targeting PPM1D specifically and the DDR and p53 pathway more generally, we sought to deepen our biological understanding of PPM1D as a drug target and determine how PPM1D inhibition differs from other therapeutic approaches to activate the DDR. We performed a high throughput screen to identify new allosteric inhibitors of PPM1D, then generated and optimized a suite of enzymatic, cell-based, and in vivo pharmacokinetic and pharmacodynamic assays to drive medicinal chemistry efforts and to further interrogate the biology of PPM1D. Importantly, this drug discovery platform can be readily adapted to broadly study the DDR and p53. We identified compounds distinct from previously reported allosteric inhibitors and showed in vivo on-target activity. Our data suggest that the biological effects of inhibiting PPM1D are distinct from inhibitors of the MDM2-p53 interaction and standard cytotoxic chemotherapies. These differences also highlight the potential therapeutic contexts in which targeting PPM1D would be most valuable. Therefore, our studies have identified a series of new PPM1D inhibitors, generated a suite of in vitro and in vivo assays that can be broadly used to interrogate the DDR, and provided important new insights into PPM1D as a drug target.

cancer biology↗

bioRxiv2024

Designing Combinatorial Multiepitope Vaccine Candidates against Scrub Typus by a Proteome-wide Immunoinfomatics Approach.

Scrub typhus (ST) is a mite-borne infection caused by the bacteria Orientia tsutsugamushi and a major public health concern in eastern and south eastern Asia. Early diagnosis and immediate intervention with antibiotics are required to limit the severity of the infection. Prophylaxis is compromised by the absence of an effective vaccine against O. tsutsugamushi. Development an effective vaccine is impeded due to extreme divergence of major surface antigens limiting cross-protectivity. Adopting a proteome-wide immunoinformatic approach, here, immunodominant outer membrane proteins are identified and conserved regions enriched in B-cell, Tc-cell, and Th-cell epitopes were mapped. Similarly, immunodominant stretches from salivary proteins of the vector were identified. Fifteen independent MEVs were designed by combining such segments and were analysed for physicochemical and immunological properties. Tertiary structure of the prioritized MEV was modelled, and interaction with TLR2, 4, and 5 was profiled through molecular docking and MD simulation. A glycosylation-deficient version of the MEV was also designed and analysed similarly. Both the MEVs were immune-simulated, which indicated elicitation of effective immune response. In silico cloning and expression were performed for bacterial and mammalian expression systems. Though the proteome-wide combinatorial approach with immunodominant segments demonstrated prospect, experimental validation for its efficacy against ST is warranted.

bioinformatics↗

bioRxiv2023

Intestinal cDC1s provide IL-12 dependent and independent functions required for CD4+ T cell mediated resistance to Cryptosporidium

Cryptosporidium is an enteric pathogen that is a prominent cause of diarrheal disease. Control of this infection requires CD4+ T cells, though the processes that lead to T cell-mediated resistance have been difficult to assess. Here, Cryptosporidium parasites that express MHCII-restricted model antigens were generated to dissect the early events that influence CD4+ T cell priming and effector function. These studies highlight that parasite-specific CD4+ T cells are primed in the draining mesenteric lymph node (mesLN) and differentiate into Th1 cells in the gut, where they mediate IFN-{gamma}-dependent control of the infection. Although type 1 conventional dendritic cells (cDC1s) were not required for initial priming of CD4+ T cells, cDC1s were required for CD4+ T cell expansion and gut homing. cDC1s were also a major source of IL-12 that was not required for priming but promoted full differentiation of CD4+ T cells and local production of IFN-{gamma}. Together, these studies reveal distinct roles for cDC1s in shaping CD4+ T cell responses to enteric infection: first to drive early expansion in the mesLN and second to drive effector responses in the gut. SummaryCryptosporidium parasites that express model antigens were generated to dissect how parasite-specific CD4+ T cells are primed and mediate effector functions required to control this enteric pathogen. cDC1s produced IL-12p40 and were required for early expansion and gut homing of CD4+ T cells. However, IL-12p40 was only required for the development of Th1 CD4+ T cell effector function in the gut.

immunology↗

bioRxiv2023

Genetic crosses within and between species of Cryptosporidium

Parasites and their hosts are engaged in rapid coevolution that balances competing mechanisms of virulence, resistance, and evasion. This often leads to host specificity, but genomic reassortment between different strains can enable parasites to jump host barriers and conquer new niches. In the apicomplexan parasite Cryptosporidium genetic exchange has been hypothesized to play a prominent role in adaptation to humans. The sexual lifecycle of the parasite provides a potential mechanism for such exchange; however, the boundaries of Cryptosporidium sex are currently undefined. To explore this experimentally, we established a model for genetic crosses. Drug resistance was engineered using a mutated phenylalanyl tRNA synthetase gene and marking strains with this and the previously used Neo transgene enabled selection of recombinant progeny. This is highly efficient, and genomic recombination is evident and can be continuously monitored in real time by drug resistance, flow cytometry, and PCR mapping. Using this approach multiple loci can now be modified with ease. We demonstrate that essential genes can be ablated by crossing a Cre recombinase driver strain with floxed strains. We further find that genetic crosses are also feasible between species. Crossing C. parvum, a parasite of cattle and humans, and C. tyzzeri a mouse parasite resulted in progeny with a recombinant genome derived from both species that continues to vigorously replicate sexually. These experiments have important fundamental and translational implications for the evolution of Cryptosporidium and open the door to reverse- and forward-genetic analysis of parasite biology and host specificity. Significance statementThe parasite Cryptosporidium is a leading cause of diarrheal disease. While infection is common all around the world, young children experiencing malnutrition are impacted most profoundly, and the disease is an important contributor to early childhood mortality. This study experimentally demonstrates that different strains and even species of Cryptosporidium can recombine their genomes through sex. The progeny of such genetic crosses shows combined features of both parents, with resistance to multiple drugs being one example. Sex thus provides a critical mechanism for the parasite to rapidly adapt to changing environments and hosts. Genetic crosses as an experimental tool may also be harnessed in the future to discover the genes underlying differences in virulence, drug sensitivity, and immunogenicity between parasite isolates.

microbiology↗

bioRxiv2023

getphylo: rapid and automatic generation of multi-locus phylogentic trees from genbank files

MotivationPhylogenetic trees are the primary tool for visualising evolutionary relationships. Traditionally, phylogenies are inferred from manually curated sets of marker genes. As available genomic data increases, there is increasing demand for tools to automatically build phylogenies from assembled genomes. Existing tools rely on reference databases of preselected marker genes, limiting their taxonomic scope. We sought to develop a tool that could quickly build phylogeny from input genomes alone. ResultsWe developed getphylo, a tool to automatically generate multi-locus phylogenetic trees from GenBank files. It has a low barrier to entry with minimal dependencies. getphylo uses a parallelised, heuristic workflow to keep runtime and system requirements as low as possible. getphylo consistently produces trees with topologies comparable to other tools in less time. Furthermore, as getphylo does not rely on reference databases, it has a virtually unlimited scope in terms of taxonomy (e.g., not limited to bacteria) and genetic scale (e.g., can analyse plasmids, prophage, and gene clusters). This combination of speed and flexibility makes getphylo a valuable addition to the phylogenetics toolkit. Availabilitygetphylo is freely available and is downloadable through the Python Package Index (pip install getphylo; https://pypi.org/project/getphylo/) and GitHub (https://github.com/drboothtj/getphylo).

bioinformatics↗

bioRxiv2023

A host AAA-ATPase exhibits bacteriolytic activity for clearance of microbial infection

An array of host cytosol guarding factors impede bacterial proliferation and preserve cellular sterility. Amongst them, proteasomal degradation of ubiquitinated pathogens has emerged as a critical mechanism for ensuring cytosolic sanctity. We wondered how proteasomes, with their small size and inability to extract membrane-bound proteins, can eradicate pathogens. Here, we unveil a unique strategy, wherein VCP/p97, a host AAA-ATPase, eliminates pathogens by exerting mechanical force that physically unfolds and pulls out ubiquitinated proteins from bacterial membrane. Combining a single-molecule approach along with molecular dynamic simulation and in-vitro reconstitution, we demonstrate that protein extraction by p97 causes extensive membrane lysis and release of cytosolic contents from phylogenetically diverse microbes. Additionally, in an in-vivo mouse sepsis model, this segregase-dependent bactericidal effect of p97 abrogated microbial proliferation in host tissues. Overall, we discovered a distinct innate antimicrobial function of p97, that protects the host against lethal bacterial infections. One Sentence SummaryA host AAA-ATPase exhibits bacteriolytic activity.

microbiology↗

bioRxiv2023

Maternal, placental and fetal response to a non-viral, polymetric nanoparticle gene therapy in nonhuman primates

BackgroundCurrently, there are no placenta-targeted treatments to alter the in utero environment. Water-soluble polymers have a distinguished record of clinical relevance outside of pregnancy. We have demonstrated the effective delivery of polymer-based nanoparticles containing a non-viral human insulin-like 1 growth factor (IGF1) transgene to correct placental insufficiency in small animal models of fetal growth restriction (FGR). Our goal was to extend these studies to the pregnant nonhuman primate (NHP) and assess maternal, placental and fetal responses to nanoparticle-mediated IGF1 treatment. MethodsPregnant macaques underwent ultrasound-guided intraplacental injections of nanoparticles (GFP- or IGF1-expressing plasmid under the control of the trophoblast-specific PLAC1 promoter complexed with a HPMA-DMEAMA co-polymer) at approximately gestational day 100 (term = 165 days). Fetectomy was performed 24 h (GFP; n =1), 48 h (IGF1; n = 3) or 10 days (IGF1; n = 3) after nanoparticle delivery. Routine pathological assessment was performed on biopsied maternal tissues, and placental and fetal tissues. Maternal blood was analyzed for complete blood count (CBC), immunomodulatory proteins and growth factors, progesterone (P4) and estradiol (E2). Placental ERK/AKT/mTOR signaling was assessed using western blot and qPCR. FindingsFluorescent microscopy and in situ hybridization confirmed placental uptake and transgene expression in villous syncytiotrophoblast. No off-target expression was observed in maternal and fetal tissues. Histopathological assessment of the placenta recorded observations not necessarily related to the IGF1 nanoparticle treatment. In maternal blood, CBCs, P4 and E2 remained within the normal range for pregnant macaques across the treatment period. Changes to placental ERK and AKT signaling at 48 h and 10 d after IGF1 nanoparticle treatment indicated an upregulation in placental homeostatic mechanisms to prevent over activity in the normal pregnancy environment. InterpretationMaternal toxicity profile analysis and lack of adverse reaction to nanoparticle-mediated IGF1 treatment, combined with changes in placental signaling to maintain homeostasis indicates no deleterious impact of treatment. FundingNational Institutes of Health, and Wisconsin National Primate Research Center.

physiology↗