Biology subjects

Andrews, D.

Publications and source records attributed to Andrews, D..

17 recordsLinked to original sources

bioRxiv2026

NOTCH3 Modulation of Extracellular Matrix, Cytoskeletal Organisation and Metabolic Functions in Human Vascular Smooth Muscle Cells

NOTCH3 is a transmembrane receptor highly expressed in vascular mural cells where it contributes to blood vessel formation and homeostasis. NOTCH3 expression declines in the vasculature with aging, and dysregulated NOTCH3 signalling is implicated in pulmonary arterial hypertension, cancer progression and CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy). RNA-based approaches targeting NOTCH3 are emerging as potential therapeutic strategies, however, the consequences of NOTCH3 suppression in mature vascular smooth muscle cells (VSMCs) remain incompletely understood. Here, we investigated the molecular and functional effects of siRNA-mediated NOTCH3 knockdown in human aortic smooth muscle cells. Transfection with NOTCH3-targeting siRNA efficiently suppressed NOTCH3 transcript and protein levels. Quantitative proteomics revealed remodelling of extracellular matrix (ECM), cytoskeletal and metabolic pathways, with enrichment of collagen biosynthesis and inhibition of glycolytic signalling. Specifically, NOTCH3 knockdown increased ECM components, including COL3A1, elevated F-actin, and upregulated the actin regulator, CTTN. In parallel, glycolytic capacity was reduced, accompanied by decreased expression of the glycolytic enzyme ENO2. Despite reduced VEGFA and alteration in angiogenic signalling proteins, endothelial network formation in co-cultures, as well as VSMC proliferation and migration remained unaffected. Finally, NOTCH3 interactome analysis revealed key collagen and actin-regulating proteins. These findings identify NOTCH3 as an important regulator of ECM homeostasis, cytoskeletal organisation, and glycolytic metabolism. The preservation of primary cellular functions despite molecular remodelling highlights the adaptive capacity of VSMCs. These findings demonstrate that therapeutic modulation of NOTCH3 may alter vascular cell biology which warrants consideration during development of RNA-based therapeutics for CADASIL and other NOTCH3-associated diseases.

molecular biology↗

bioRxiv2026

Transposable element disruption of a second thyroglobulin-like gene confers Vip3Aa resistance in Helicoverpa armigera

BackgroundThe cotton bollworm Helicoverpa armigera is a major global pest controlled by genetically engineered crops expressing Bacillus thuringiensis (Bt) toxins, including Vip3Aa. While Vip3Aa is widely deployed, the genetic basis of resistance remains poorly understood. Previous work identified disruption of a thyroglobulin-like gene (HaVipR1) as one mechanism of resistance, suggesting additional loci may be involved. ResultsUsing linkage analysis, transcriptomics, long-read sequencing, and CRISPR-Cas9 gene editing, we identify a second thyroglobulin-like gene, HaVipR2, as a novel mediator of Vip3Aa resistance. Resistance in a field-derived H. armigera line was shown to be monogenic, recessive, and autosomal, mapping to chromosome 29. Long-read sequencing revealed a [~]16 kb transposable element insertion disrupting HaVipR2, which was undetectable using standard short-read approaches. CRISPR-Cas9 knockout of HaVipR2 conferred >900-fold resistance, confirming its causal role. Comparative analyses show that HaVipR1 and HaVipR2 share conserved domain architecture, indicating that thyroglobulin-domain proteins represent a recurrent target of resistance evolution. ConclusionsOur findings establish thyroglobulin-domain proteins as a new class of Bt resistance genes in Lepidoptera and demonstrate that transposable element insertions can drive adaptive resistance while evading detection by conventional methods. These results highlight the importance of long-read sequencing and accurate genome annotation for resistance monitoring and provide new insights into the molecular basis and evolution of Vip3Aa resistance.

genomics↗

bioRxiv2025

Efineptakin alfa (NT-I7) improves overall survival and induces tertiary lymphoid structures in murine lung tumors

Tertiary lymphoid structures (TLSs) are emerging as good predictive biomarkers of response to cancer immunotherapy. However, therapeutic strategies to induce these structures are currently limited. We evaluated the therapeutic benefit of efineptakin alfa (NT-I7), a long-acting form of IL-7, and its ability to induce TLSs in a murine lung tumor model. NT-I7 improved overall survival in tumor-bearing mice. It also increased the abundance of T, B, dendritic cells, and stem-like CD8 T cells and promoted the formation of immune aggregates in the tumor microenvironment (TME). Stem-like CD8 T cells were preferentially located in the immune aggregates. Spatial transcriptomic analyses of the TME further demonstrated that the immune aggregates induced by NT-I7 included TLSs with enrichment of Cd274 (PD-L1) transcripts and genes involved in antigen processing and presentation. Upregulation of Cd274 in the TLSs may provide opportunities for synergy between NT-I7 and PD-1-targeted immunotherapy. STATEMENT OF SIGNIFICANCEThis study demonstrates the ability of efineptakin alfa (NT-I7) to potentially augment the clinical efficacy of cancer immunotherapy by inducing tertiary lymphoid structures in the tumor microenvironment.

immunology↗

bioRxiv2024

Functionally constrained human proteins are less prone to disruption of stability caused by single amino acid substitutions

It is well understood that missense mutations that disrupt protein structural stability are a common pathogenic mechanism in human genetic disease. At a proteome-wide scale, we have quantitated potential disruption of protein stability due to amino acid substitution and show that the most functionally constrained proteins are typically less susceptible to large mutational changes in stability. Mechanistically, this relates to greater intrinsic disorder among constrained proteins, but also to increased B-factors in the ordered regions of constrained proteins. This phenomenon means that constrained proteins exhibit smaller stability effects due missense mutations, and partly explains why overtransmission of pathogenic missense variation is less prevalent in genetic disorders characterised with protein truncating variation. From analysis of the predicted protein stability effects of missense genetic variation across all human proteins, we show that the most functionally constrained proteins are depleted of both destabilising ({Delta}{Delta}G > 0.5 kcal/mol) and overly-stabilising ({Delta}{Delta}G < -0.5 kcal/mol) amino acid variation in disease-free populations. Despite this, amino acid substitutions with large stability effects in functionally constrained proteins are still highly prevalent among pathogenic human genetic variation. Importantly, we observe that there are approximately five times more missense variants with large stability effects than there are unambiguous loss-of-function mutations. Missense variants with disruption of stability effects recapitulate the per-gene patterns of functional constraint observed with protein truncating loss-of-function variation, yet their relative abundance abrogates difficulties encountered when estimating functional constraint for the shortest human genes.

genomics↗

bioRxiv2024

The West African lungfish secretes a living cocoon during aestivation with uncertain antimicrobial function

One of the most exceptional adaptations to extreme drought is found in the sister group to tetrapods, the lungfishes (Dipnoi), which can aestivate inside a mucus cocoon for multiple years at reduced metabolic rates with complete cessation of ingestion and excretion. However, the function of the cocoon tissue is not fully understood. Here we developed a new more natural laboratory protocol for inducing aestivation in the West African lungfish, Protopterus annectens, and investigated the structure and function of the cocoon. We used electron microscopy and imaging of live tissue-stains to confirm that the inner and outer layers of the paper-thin cocoon are composed primarily of living cells. However, we also repeatedly observed extensive bacterial and fungal growth covering the cocoon and found no evidence of anti-microbial activity in vitro against E. coli for the cocoon tissue in this species. This classroom discovery-based research, performed during a course-based undergraduate research experience course (CURE), provides a robust laboratory protocol for investigating aestivation and calls into the question the function of this bizarre vertebrate adaptation.

physiology↗

bioRxiv2023

The carboxyl-terminal sequence of PUMA binds to both anti-apoptotic proteins and membranes.

Anti-apoptotic proteins such as BCL-XL promote cell survival by sequestering pro-apoptotic BCL-2 family members, an activity that frequently contributes to tumorigenesis. Thus, the development of small-molecule inhibitors for anti-apoptotic proteins, termed BH3-mimetics, is revolutionizing how we treat cancer. BH3 mimetics kill cells by displacing sequestered pro-apoptotic proteins to initiate tumor-cell death. Recent evidence has demonstrated that in live cells the BH3-only proteins PUMA and BIM resist displacement by BH3-mimetics, while others like tBID do not. Analysis of the molecular mechanism by which PUMA resists BH3-mimetic mediated displacement from full-length anti-apoptotic proteins (BCL-XL, BCL-2, BCL-W and MCL-1) reveals that both the BH3-motif and a novel binding site within the carboxyl-terminal sequence (CTS) of PUMA contribute to binding. Together these sequences bind to anti-apoptotic proteins, which effectively "double-bolt locks" the proteins to resist BH3-mimetic displacement. The pro-apoptotic protein BIM has also been shown to double-bolt lock to anti-apoptotic proteins however, the novel binding sequence in PUMA is unrelated to that in the CTS of BIM and functions independent of PUMA binding to membranes. Moreover, contrary to previous reports, we find that when exogenously expressed, the CTS of PUMA directs the protein primarily to the endoplasmic reticulum (ER) rather than mitochondria and that residues I175 and P180 within the CTS are required for both ER localization and BH3-mimetic resistance. Understanding how PUMA resists BH3-mimetic displacement will be useful in designing more efficacious small-molecule inhibitors of anti-apoptotic BCL-2 proteins.

cell biology↗

bioRxiv2022

QRATER: a collaborative and centralized imaging quality control web-based application.

Quality control (QC) is an important part of all scientific analysis, including neuroscience. With manual curation considered the gold standard, there remains a lack of available tools that make manual neuroimaging QC accessible, fast, and easy. In this article we present Qrater, a containerized web-based python application that enables viewing and rating of previously generated QC images. A group of raters with varying amounts of experience in QC evaluated Qrater in three different tasks: QC of MRI raw acquisition (10,196 images), QC of non-linear registration to a standard template (10,196 images) and QC of skull segmentation (6,968 images). We measured the proportion of failed images, timing and intra- and inter-rater agreement. Raters spent vastly different amounts of time on each image depending on their experience and the task at hand. QC of MRI raw acquisition was the slowest. While an expert rater needed approximately one minute, trained raters spent 2-6 minutes evaluating an image. The fastest was the curation of a skull segmentation image, where expert raters spent on average 3 seconds per image before assigning a rating. Rating agreement also varied depending on the experience of the raters and the task at hand: trained raters inter-rater agreement with the experts gold standard ranged from fair to substantial in raw acquisition (Cohens chance corrected kappa agreement scores up to 0.72) and from fair to excellent in linear registration (kappa scores up to 0.82), while the experts inter-rater agreement of the skull segmentation task was excellent (kappa = 0.83). These results demonstrate that Qrater is a useful asset for QC tasks that rely on manual curation of images.

bioinformatics↗

bioRxiv2021

StabilitySort: assessment of protein stability changes on a genome-wide scale to prioritise potentially pathogenic genetic variation

SummaryMissense mutations that change protein stability are strongly associated with human inherited genetic disease. With the recent availability of predicted structures for all human proteins generated using the AlphaFold2 prediction model, genome-wide assessment of the stability effects of genetic variation can, for the first time, be easily performed. This facilitates the interrogation of personal genetic variation for potentially pathogenic effects through the application of stability metrics. Here, we present a novel algorithm to prioritise variants predicted to strongly destabilise essential proteins, available as both a standalone software package and a web-based tool. We demonstrate the utility of this tool by showing that at values of the Stability Sort Z-score above 1.6, pathogenic, protein-destabilising variants from ClinVar are detected at a 58% enrichment, over and above the destabilising (but presumably non-pathogenic) variation already present in the HapMap NA12878 genome. Availability and ImplementationStabilitySort is available as both a web service (http://130.56.244.113/StabilitySort/) and can be deployed as a standalone system (https://gitlab.com/baaron/StabilitySort). ContactDan.Andrews@anu.edu.au

bioinformatics↗

bioRxiv2021

Charting Brain Growth and Aging at High Spatial Precision

Defining reference models for population variation, and the ability to study individual deviations is essential for understanding inter-individual variability and its relation to the onset and progression of medical conditions. In this work, we assembled a reference cohort of neuroimaging data from 82 sites (N=58,836; ages 2-100) and use normative modeling to characterize lifespan trajectories of cortical thickness and subcortical volume. Models are validated against a manually quality checked subset (N=24,354) and we provide an interface for transferring to new data sources. We showcase the clinical value by applying the models to a transdiagnostic psychiatric sample (N=1,985), showing they can be used to quantify variability underlying multiple disorders whilst also refining case-control inferences. These models will be augmented with additional samples and imaging modalities as they become available. This provides a common reference platform to bind results from different studies and ultimately paves the way for personalized clinical decision making.

neuroscience↗

bioRxiv2021

Dysregulation of PAX5 causes uncommitted B cell development and tumorigenesis in mice

PAX5 is the master transcription factor controlling B cell identity. In humans, mutations in PAX5 account for 30% of B cell acute lymphoblastic leukemia (B-ALL) cases. Investigating the causal effects of PAX5 mutations has however been difficult due to the premature lethality of Pax5-/- mice. Here we describe a novel mouse strain with a premature STOP mutation in Pax5 (Y351*) that produces a truncated protein and reduction in protein function, yet still allows for some B cell development to occur. A population of uncommitted and multipotent CD19+B220- B cells develops in the bone marrow of homozygous mice leading to the development of B-ALL. We show that the tumors frequently acquire secondary mutations in Jak3, and Ptpn11 highlighting key pathways interacting with PAX5 during malignant transformation. Analysis of the PAX5Y351* mice provide insight not only into the functional consequence of reduced PAX5 activity on B cell development and identity, but also provides an avenue in which to study PAX5-driven B-ALL in mice. One Sentence SummaryReduction in PAX5 function in mice induces the development of uncommitted B cells that have multipotent and malignant potential.

immunology↗

bioRxiv2020

Assessment of differentially methylated loci in individuals with end-stage kidney disease attributed to diabetic kidney disease

A subset of individuals with type 1 diabetes mellitus (T1DM) are predisposed to developing diabetic kidney disease (DKD), which is the most common cause globally of end-stage kidney disease (ESKD). Emerging evidence suggests epigenetic changes in DNA methylation may have a causal role in both T1DM and DKD. The aim of this investigation was to assess differences in blood-derived DNA methylation patterns between individuals with T1DM-ESKD and individuals with long-duration T1DM but no evidence of kidney disease upon repeated testing. Blood-derived DNA from individuals (107 cases, 253 controls and 14 experimental controls) were bisulphite treated before DNA methylation patterns from both groups were generated and analysed using Illuminas Infinium MethylationEPIC BeadChip arrays (n=862,927 sites). Differentially methylated CpG sites (dmCpGs) were identified (false discovery rate adjusted p[≤]x10-8 and fold change {+/-}2) by comparing methylation levels between ESKD cases and T1DM controls at single site resolution. Gene annotation and functionality was investigated to enrich and rank methylated regions associated with ESKD in T1DM. Top-ranked genes within which several dmCpGs were located and supported by in silico functional data, and replication where possible, include; AFF3, ARID5B, CUX1, ELMO1, FKBP5, HDAC4, ITGAL, LY9, PIM1, RUNX3, SEPTIN9, and UPF3A. Top-ranked enrichment pathways included pathways in cancer, TGF-{beta} signalling and Th17 cell differentiation. Epigenetic alterations provide a dynamic link between an individuals genetic background and their environmental exposures. This robust evaluation of DNA methylation in carefully phenotyped individuals, has identified biomarkers associated with ESKD, revealing several genes and implicated key pathways associated with ESKD in individuals with T1DM.

molecular biology↗

bioRxiv2020

Atypical B cells are a normal component of immune responses to vaccination and infection in humans

The full diversity of the circulating human B cell compartment is unknown. Flow cytometry analysis suggests that in addition to naive and memory B cells, there exists a population of CD11c+, CD27- CD21- "atypical" B cells, that are associated with chronic or recurrent infection and autoimmunity. We used single cell RNA-seq approaches to examine the diversity of both antigen-specific B cells and total B cells in healthy subjects and individuals naturally-exposed to recurrent malaria infections. This analysis revealed two B cell lineages: a classical lineage of activated and resting memory B cells, and an atypical-like lineage. Surprisingly, the atypical lineage was common in both malaria exposed individuals and non-exposed healthy controls. Using barcoded antibodies in conjunction with our transcriptomic data, we found that atypical lineage cells in healthy individuals lack many atypical B markers and thus represent an undercounted cryptic population. We further determined using antigen specific probes that atypical cells can be induced by primary vaccination in humans and can be recalled upon boosting. Collectively these data suggest that atypical cells are not necessarily pathogenic but can be a normal component of B responses to antigen.

immunology↗

bioRxiv2019

Absence of pathogenic Short Tandem Repeat expansions in Systemic Lupus Erythematosus disease-associated genes

Short tandem repeat (STR) expansions have been shown to be pathogenic in human neurological diseases, such as Huntington disease. Yet, the potential role of STRs in non-neurological diseases has yet to be fully investigated. In this study, the potential role of STR expansions in the pathogenesis of systemic lupus erythematosus (SLE) was investigated using patient genomic data and two computational tools, HipSTR and exSTRa. The length variability of STRs in 76 SLE-associated genes was compared using exome data from 271 SLE affected individuals and 158 of their unaffected relatives. We conclude that no large STR expansions associated with SLE were present in these affected individuals within the 76 genes investigated. Lack of evidence does not negate a pathogenic role for STR expansions in SLE, yet given the number of individuals included in this study, we expect that this is not a common source of pathogenesis in SLE.\n\nSignificance statementThe increasing availability and decreasing cost of sequencing genomes lends itself to computational analysis, extracting information to aid diagnosis, guide treatment or discover disease mechanisms and new treatments. Computational tools have been developed to look for various types of mutations, including short tandem repeats (STRs), which has been shown to cause diseases such as Huntington disease. Limited research on the possible role of STR expansions in systemic lupus erythematosus (SLE) has been done. Here we use computational tools to compare the length of STRs in 76 SLE-associated genes in patients and their unaffected relatives. Our results did not identify any large STR expansions associated with SLE, and further research is required to gain a better understanding of this complex disease.

genomics↗

bioRxiv2019

The carboxyl-terminal sequence of Bim enables Bax activation and killing of unprimed cells

The Bcl-2 family BH3 protein Bim promotes apoptosis at mitochondria by activating the pore forming proteins Bax and Bak and by inhibiting the anti-apoptotic proteins Bcl-XL, Bcl-2 and Mcl-1. Bim binds to these proteins via its BH3 domain and to the mitochondrial membrane by a carboxyl-terminal sequence (CTS). In cells killed by Bim, the expression of a Bim mutant in which the CTS was deleted (BimL-dCTS) triggered variable amounts of apoptosis that correlated with inhibition of anti-apoptotic proteins being sufficient to permeabilize mitochondria isolated from the same cells. Detailed analysis of the molecular mechanism demonstrated that BimL-dCTS inhibited Bcl-XL but did not activate Bax. Our examination of additional point mutants unexpectedly revealed that the CTS of Bim is required for physiological concentrations of Bim to activate Bax and that different residues in the CTS enable Bax activation and binding to membranes.

biochemistry↗

bioRxiv2019

Improving drug discovery using image-based multiparametric analysis of epigenetic landscape.

With the advent of automatic cell imaging and machine learning, high-content phenotypic screening has become the approach of choice for drug discovery due to its ability to extract drug specific multilayered data and compare it to known profiles. In the field of epigenetics such screening approaches has suffered from the lack of tools sensitive to selective epigenetic perturbations. Here we describe a novel approach Microscopic Imaging of Epigenetic Landscapes (MIEL) that captures patterns of nuclear staining of epigenetic marks (e.g. acetylated and methylated histones) and employs machine learning to accurately distinguish between such patterns (1). We demonstrated that MIEL has superior resolution compared to conventional intensity thresholding techniques and enables efficient detection of epigenetically active compounds, function-based classification, flagging possible off-target effects and even predict novel drug function. We validated MIEL platform across multiple cells lines and using dose-response curves to insure the robustness of this approach for the high content high throughput drug discovery.

cell biology↗

bioRxiv2018

Genome-wide association study of diabetic kidney disease highlights biology involved in renal basement membrane collagen

Diabetic kidney disease (DKD) is a heritable but poorly understood complication of diabetes. To identify genetic variants predisposing to DKD, we performed genome-wide association analyses in 19,406 individuals with type 1 diabetes (T1D) using a spectrum of DKD definitions basedon albuminuria and renal function. We identified 16 genome-wide significant loci. The variant with the strongest association (rs55703767) is a common missense mutation in the collagen type IV alpha 3 chain (COL4A3) gene, which encodes a major structural component of the glomerular basement membrane (GBM) implicated in heritable nephropathies. The rs55703767 minor allele (Asp326Tyr) is protective against several definitions of DKD, including albuminuria and end-stage renal disease. Three other loci are in or near genes with known or suggestive involvement in DKD (BMP7) or renal biology (COLEC11 and DDR1). The 16 DKD-associated loci provide novel insights into the pathogenesis of DKD, identifying potential biological targets for prevention and treatment.

genetics↗

bioRxiv2018

Multiparametric Signature of Glioblastoma Differentiation Revealed by Imaging of Cellular Epigenetic Landscapes

The resistance of Glioblastoma (GBM) to conventional cytotoxic drugs has prompted novel therapeutic strategies, including differentiating tumor propagating cells (TPCs) into less tumorigenic cells using small molecule inducers of TPC differentiation. However, high-throughput screening for such molecules is hampered by the lack of robust markers of GBM differentiation. To obtain a signature of differentiated TPCs, we developed \"Microscopic Imaging of Epigenetic Landscapes\" (MIEL), which captures patterns of nuclear staining for epigenetic marks to derive feature-fingerprints of individual cells. We confirmed MIELs ability to accurately distinguish multiple cell fates and identified a multiparametric epigenetic signature of differentiated TPCs. Critically, we validated epigenetic imaging-based signature using global gene expression thus providing the proof of principle for the MIELs ability to select and prioritize small molecules, which induce TPC differentiation.

cancer biology↗