Biology subjects

Gill, K.

Publications and source records attributed to Gill, K..

9 recordsLinked to original sources

bioRxiv2026

Brain structural and genetic correlates of motor coordination and learning behaviours: modelling developmental coordination disorder

Developmental coordination disorder (DCD) is a common neurodevelopmental condition characterized by impaired motor coordination and learning, yet its neurobiological and genetic bases remain poorly understood. Here, we leverage the BXD recombinant inbred mouse panel to model the polygenic architecture of DCD and link behaviour, brain structure, and genotype. High-resolution ex vivo MRI across 14 strains revealed that DCD-like mice have modestly reduced total brain volume, with a distinct neuroanatomical profile characterized by enlarged cortical regions alongside reduced cerebellar, thalamic, and other subcortical volumes. These structural differences closely mirror findings reported in human DCD. Across strains, variation in brain structure strongly correlated with motor behaviours, with coordinated patterns linking increased cortical and decreased subcortical volumes to poorer motor coordination, while more focal associations were observed for motor learning. Multivariate analysis identified a dominant brain-behaviour axis capturing this cortical-subcortical trade-off. Quantitative trait locus (QTL) mapping revealed multiple loci influencing regional brain volumes, including a prominent locus on chromosome 12 regulating cerebellar structures, but did not identify single loci driving the main multivariate brain-behaviour relationships, consistent with a distributed genetic architecture. Together, these findings demonstrate that DCD-like motor impairments arise from coordinated alterations across distributed brain systems under polygenic control. This work establishes a translational framework linking genetic variation to brain organization and motor function, and suggests that DCD reflects the extreme of a continuous spectrum of neurobiological variation rather than a discrete condition.

neuroscience↗

bioRxiv2025

Non-human primate LIBRA-Seq accelerates neutralizing antibody discovery in RM vaccinated against HIV-1

Broadly neutralizing antibodies (bNAbs) exhibit protective efficacy against HIV-1 infection making them an ideal archetype for HIV-1 vaccine design. Presently, no vaccine candidate has induced antibody responses capable of meaningful protection against the swathe of circulating, difficult to neutralize tier 2 HIV-1 viruses. However, the development of stabilized, native-like envelope (Env) trimers such as BG505.SOSIP.664.T332N (BG505 SOSIP) has marked a significant advancement in vaccine design, due to their ability to elicit NAbs that neutralize tier 2 viruses in rhesus macaques (RM). NAb development following envelope trimer immunization in RM remains poorly understood, with hypothesized contributions from genetic variation at the IG loci, naive B cell repertoire, and differential gene expression in B cell lineages. To address these knowledge gaps, we have developed a set of BG505 SOSIP probes capable of recovering paired clonotype identity, antigen specificity, and gene expression of B cells in a high throughput fashion. These probes were constructed by conjugating biotinylated BG505 SOSIP to streptavidin covalently linked to both sc-RNA-Seq compatible DNA oligonucleotides and flow cytometry compatible fluorophores. Using these reagents, we isolated and sequenced BG505 SOSIP specific memory B cells from the PBMCs of an RM that developed high titers of neutralizing antibodies. To benchmark the accuracy of our technology, we compared our recovered heavy and light chain sequences to those identified from the same animal using conventional methodology and recovered 100% of previously identified NAbs. We then applied this technology to recover BG505 SOSIP specific memory B cells from five additional vaccinated RMs, cloned 34 antibodies for functional characterization, and identified ten antibodies with autologous neutralizing activity. Author SummaryUnderstanding how effective antibodies arise after HIV vaccination is essential for developing a protective vaccine, yet studying these responses in non-human primates has been limited by low- throughput methods. In this study, we adapted a high-throughput single-cell sequencing approach to identify HIV envelope-specific antibodies from vaccinated rhesus macaques. This method allowed us to recover paired antibody sequences together with their antigen specificity from thousands of individual B cells. We successfully identified known neutralizing antibodies and discovered additional antibodies capable of neutralizing HIV across multiple animals. Our analysis revealed that vaccine-elicited antibody responses were dominated by a small number of expanded lineages, with shared genetic features among animals with stronger neutralization. These findings demonstrate that this approach can efficiently define the antibody repertoires generated by HIV vaccines and provide a powerful tool for evaluating and improving immunogens in preclinical vaccine studies.

immunology↗

bioRxiv2025

Circulating Chlamydia trachomatis-specific T Cell Immunity Reflects Widespread Exposure in South African Adolescents and Young Women

Chlamydia trachomatis remains the most prevalent bacterial sexually transmitted infection worldwide, with adolescent girls and young women (AGYW) disproportionately affected. Despite this, vaccine development is hindered by our limited understanding of protective immunity, particularly in the context of recurrent infections and immune-mediated pathology. Here, we characterised mucosal inflammation and systemic immune responses to C. trachomatis in South African AGYW (n=145), stratified by exposure history based on nucleic acid amplification testing (NAAT) and anti-C. trachomatis IgG levels. Cervicovaginal cytokines were quantified from menstrual cup secretions, and cervical and peripheral blood T cell activation assessed by flow cytometry. CD4+ T cell responses to recombinant MOMP were measured in a subset of 46 women who were NAAT-positive and/or seropositive. Untreated or recurrent C. trachomatis infection (NAAT+/IgG+) was associated with increased cervical T cell activation. All women with untreated or recurrent infections had detectable circulating C. trachomatis-specific CD4+ T cells in blood; however, response magnitude was 2.4-fold lower than in women with cleared or primary infections. Women with cleared infection had the highest proportions of C. trachomatis-specific multifunctional CD4+ T cells, while those with untreated or recurrent infections had almost none. Notably, systemic C. trachomatis-specific Th1 responses were inversely correlated with genital tract concentrations of inflammatory cytokines including IL-1{beta}, TNF, and IL-17. These findings demonstrate that both the magnitude and quality of the systemic CD4+ T cell responses are critical components of protective immunity to C. trachomatis, and may limit mucosal immunopathology, which has important implications for vaccine strategies and evaluation in high-risk populations.

immunology↗

bioRxiv2023

B cell repertoire in children with skin barrier dysfunction supports altered IgE maturation associated with allergic food sensitization

IgE B cells produce antibodies responsible for the inappropriate specificity seen in allergic disease. In this study, we sequence antibody gene repertoires from a large, well-characterized early life cohort at risk for developing food allergy. We found that food allergen sensitization was associated with lower IgE mutation frequencies that was abrogated in children living with a pet dog, suggesting potential molecular mechanisms underlying the hygiene hypothesis (i.e., protective effects of pet ownership and non-antiseptic environs reported for allergic disease). We also observed increased IgE diversity and increased isotype-switching to IgE, suggesting that B cell development is altered in those with food allergen sensitizations relative to those without. IgE diversity was even more extreme in subjects who were highly likely to be peanut allergic. Unlike food antigen sensitization, we detected no effect of aeroallergen sensitization on IgE mutation levels and diversity. Consistent patterns of antibody rearrangement were associated with food allergen sensitization. These results have important implications for the allergic response driven by mast cells and basophils and the underlying drivers of the atopic march.

immunology↗

bioRxiv2022

Investigating mouse motor coordination using quantitative trait locus analysis to model the genetic underpinnings of developmental coordination disorder

The fundamental skills for motor coordination and motor control emerge through development, from infancy to late childhood years. Neurodevelopmental disorders such as Developmental Coordination Disorder (DCD) lead to impaired acquisition of motor skills. This study investigated motor behaviors that reflect the core symptoms of human DCD through the use of BXD recombinant inbred lines of mice that are known to have divergent phenotypes in many behavioral traits, including motor activity. We sought to correlate behavior in basic motor control tasks with the known genotypes of these reference populations of mice using quantitative trait locus (QTL) mapping. We used twelve BXD lines with an average of 16 mice per group to assess the onset of reflexes during the early neonatal stage of life and differences in motor coordination using the open field, rotarod, and gait analyses during the adolescent/young adulthood period. Results indicated significant variability between lines in as to when neonatal reflexes appeared as well as significant line differences for all measures of motor coordination. Five lines (BXD15, BXD27, BXD28, BXD75, and BXD86) struggled with sensorimotor coordination as seen in gait analysis, rotarod, and open field, similar to human presentation of DCD. We identified three significant quantitative trait loci for gait on proximal Chr 3, Chr 4 and distal Chr 6. Based on expression, function, and polymorphism within the mapped QTL intervals, 7 candidate genes (Gpr63, Spata5, Trpc3, Cntn6, Chl1, Grm7 and Ogg1) emerged. This study offers new insights into mouse motor behavior which promises to be a first murine model to explore the genetics and neural correlates of DCD.

neuroscience↗

bioRxiv2022

Two therapeutic CRISPR/Cas9 gene editing approaches revert FTD/ALS cellular pathology caused by a C9orf72 repeat expansion mutation in patient derived cells

CRISPR gene editing holds promise to cure or arrest genetic disease, if we can find and implement curative edits reliably, safely and effectively. Expansion of a hexanucleotide repeat in C9orf72 is the leading known genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). We evaluated three approaches to editing the mutant C9orf72 gene for their ability to correct pathology in neurons derived from patient iPSCs: excision of the repeat region, excision of the mutant allele, and excision of regulatory region exon 1A. All three approaches normalized RNA abnormalities and TDP-43 pathology, but only repeat excision and mutant allele excision completely eliminated pathologic dipeptide repeats. Our work sheds light on the complex regulation of the C9orf72 gene and suggests that because of sense and anti-sense transcription, silencing a single regulatory region may not reverse all pathology. Our work also provides a roadmap for evaluating CRISPR gene correction using patient iPSCs.

neuroscience↗

bioRxiv2022

Developmental Coordination Disorder: What Can We Learn From Recombinant Inbred Mice Using Motor Learning Tasks and Quantitative Trait Locus Analysis

Developmental Coordination Disorder (DCD) is a motor skills disorder that affects 5-6% of all school-aged children. There is an indication that DCD has an underlying genetic component due to its high heritability. Therefore, we we have explored the use of a recombinant inbred family of mice known as the BXD panel to understand the genetic basis of complex traits (i.e., motor learning) through identification of Quantitative Trait Loci (QTLs). The overall aim of this study was to utilize the QTL approach to evaluate the genome-to-phenome correlation in BXD strains of mice in order to to better understanding the human presentation of DCD. Results in this current study indicate there is a spectrum of motor learning in the pre-selected BXD strains of mice with a spectrum between high and low learning capabilities. Five lines - BXD15, BXD27, BXD28, BXD75, and BXD86 - exhibited the most DCD-like phenotype, when compared to other BXD lines of interest. The results indicate that BXD15 and BXD75 struggled primarily with gross motor skills, BXD28 primarily had difficulties with fine motor skills, and BXD27 and BXD28 lines struggled with both fine and gross motor skills. The functional roles of significant QTL genes were assessed in relation to DCD-like behavior. Only Rab3a (Ras-related protein Rab-3A) emerged as a best candidate gene for the horizontal ladder rung task. This gene is found to be associated with brain and skeletal muscle development. This is the first study to specifically examine the genetic linkage of DCD using BXD lines of mice.

neuroscience↗

bioRxiv2019

Dual SMAD inhibition and Wnt inhibition enhances the differentiation of induced pluripotent stem cells into Retinal Ganglion cells (iPSC-RGCs)

Glaucoma is a group of progressive optic neuropathies that share common biological and clinical characteristics including irreversible changes to the optic nerve and visual field loss caused by death of retinal ganglion cells (RGCs). The loss of RGCs manifests as characteristic cupping or optic nerve degeneration, resulting in visual field loss in patients with Glaucoma. Published studies on in vitro RGC differentiation from stem cells utilized classical RGC signaling pathways mimicking retinal development in vivo. Although many strategies allowed for the generation of RGCs, increased variability between experiments and lower yield hampered the cross comparison between individual lines and between experiments. To address this critical need, we developed a reproducible chemically defined in vitro methodology for generating retinal progenitor cell (RPC) populations from iPSCs, that are efficiently directed towards RGC lineage. Using this method, we reproducibly differentiated iPSCs into RGCs with greater than 80% purity, without any genetic modifications. We used small molecules and peptide modulators to inhibit BMP, TGF-{beta} (SMAD), and canonical Wnt pathways that reduced variability between iPSC lines and yielded functional and mature iPSC-RGCs. Using CD90.2 antibody and Magnetic Activated Cell Sorter (MACS) technique, we successfully purified Thy-1 positive RGCs with nearly 95% purity.

neuroscience↗

bioRxiv2018

High-resolution mass spectrometry-based non-targeted metabolomic discovery of disease and glucocorticoid biomarkers in an animal model of muscular dystrophy

Urine is increasingly being considered as a source of biomarker development in Duchenne Muscular Dystrophy (DMD), a severe, life-limiting disorder that affects approximately 1 in 4500 boys. In this study, we used the mdx mice--a murine model of DMD--to discover biomarkers of disease, as well as pharmacodynamic biomarkers responsive to prednisolone, commonly used to treat DMD. Longitudinal urine samples were analyzed from male age-matched mdx and wild-type mice randomized to prednisolone or vehicle. We used high-resolution mass spectrometry to discover metabolic biomarkers of both disease and glucocorticoid treatment. A large number of metabolites (869 out of 6,334) were found to be significantly different between mdx and wild-type mice at baseline (Bonferroni-adjusted p-value < 0.05), thus being associated with disease status. These included a peak with m/z=357 and creatine, which were also discovered in a previous human study looking at serum. Novel observations included biliverdin and hypusine. These four peaks were also significantly higher in mdx mice compared to wild-type, as well as significantly associated with time after the baseline. Creatine and biliverdin were also associated with treatment after the baseline, but the association with creatine may have been driven by an imbalance at baseline. In conclusion, our study reports a number of biomarkers, both known and novel, which may be related to either the mechanisms of muscle injury in DMD and/or prednisolone treatment.

bioinformatics↗