Biology subjects

Henderson, N.

Publications and source records attributed to Henderson, N..

9 recordsLinked to original sources

bioRxiv2025

ASD mutations in the ciliary gene CEP41 impact development of projection neurons and interneurons in a human cortical organoid model

Primary cilia control cell-cell signalling and their dysfunction has been implicated in Autism Spectrum Disorders (ASD) but their roles in the ASD aetiology remain largely unexplored. Here, we analysed the impact of ASD mutations in CEP41 using human corticogenesis. CEP41 encodes a centrosomal protein located at the basal body and the ciliary axoneme and is mutated in ASD individuals and in Joubert syndrome, a ciliopathy with high incidence of ASD. To gain insights into CEP41s role in ASD aetiology, we characterised human cortical organoids carrying the CEP41 R242H point mutations found in ASD individuals. This mutation did not interfere with CEP41s ciliary localisation but cilia were shorter and had lower levels of tubulin polyglutamylation, which is indicative of altered cilia stability and signalling. Moreover, scRNAseq analyses revealed that the expression of several transcription factors with critical roles in interneuron development was altered in mutant interneurons and their progenitors. The CEP41 mutation also caused decreased cortical progenitor proliferation and an augmented formation of upper layer cortical neurons. Taken together, these findings indicate that CEP41 controls excitatory and inhibitory neuron differentiation, alterations in which might lead to an excitation/inhibition imbalance that is widely recognized as a convergent mechanism underlying neurodevelopmental disorders.

developmental biology↗

bioRxiv2025

Th1 effector CD4 T cells rely on IFN-γ production to induce alopecia areata

Alopecia areata (AA) is an autoimmune disease that is clinically characterized by hair loss and histologically by a peribulbar infiltrate of CD8 and CD4 T cells. Prior studies have focused on the role of CD8 T cells in the development of AA; however, the role of CD4 T cells remains unclear. Here, we demonstrate that CD4 T cells from the skin draining lymph nodes (SDLN) of AA mice transferred disease into recipient mice. Further, these cells exhibited a T-helper type 1 (Th1) effector transcriptional and phenotypic profile. The pathogenic activity of these CD4 T cells was dependent upon the presence of endogenous CD8 T cells and host IFN-{gamma} responsiveness. Targeted deletion of CD4 T cell-mediated production of IFN-{gamma} abrogated the ability of this cell population to transfer disease. Together, these data provide mechanistic insights into pathways that lead to AA development, strengthening our understanding of the disease and inviting studies into exploring novel therapeutic strategies for human patients.

immunology↗

bioRxiv2023

Oncogenic RAS drives rapid onset cellular plasticity and elicits a tumour-promoting neutrophil response at the inception of preneoplastic development

Oncogenic driver mutations are frequently found in normal tissues, suggesting that additional non-genetic factors are required for tumourigenesis. Phenotypic plasticity is an important gateway to malignancy and inflammation can fuel tumourigenesis, however, little is known about when and how these hallmarks first arise. Using single-cell transcriptomics and in vivo live imaging we have characterised the immediate cell intrinsic and innate immune responses during the first 24 hours following oncogenic Ras activation, in an inducible zebrafish model of HRASG12V-mediated skin tumour initiation. We found that only a subset of basal keratinocytes, but not superficial keratinocytes, are susceptible to RAS-driven phenotypic plasticity. These preneoplastic cells undergo dedifferentiation and partial EMT, resembling malignant cells observed in human squamous cell carcinoma (SCC). Strikingly, the same subset instigates the development of tumour-promoting neutrophils, which in turn enhance preneoplastic cell proliferation. Our findings demonstrate that the effects of oncogenic Ras are primarily determined by the cell of origin and reveal an association between the unlocking of phenotypic plasticity and the onset of tumour-promoting inflammation.

cancer biology↗

bioRxiv2023

The expression of PKM1 and PKM2 in developing, benign, and cancerous prostatic tissues

Neuroendocrine prostate cancer (NEPCa) is the most aggressive type of prostate cancer. However, energy metabolism, one of the hallmarks of cancer, in NEPCa has not been well studied. Pyruvate kinase M (PKM), which catalyzes the final step of glycolysis, has two main splicing isoforms, PKM1 and PKM2. PKM2 is known to be upregulated in various cancers, including prostate adenocarcinoma (AdPCa). In this study, we used immunohistochemistry, immunofluorescence staining, and bioinformatic analysis to examine the expression of PKM1 and PKM2 in mouse and human prostatic tissues, including developing, benign and cancerous prostate. We found that PKM2 was the predominant isoform expressed throughout prostate development and PCa progression, with slightly reduced expression in some NEPCa samples. PKM1 was mostly expressed in stromal cells but low-level PKM1 was also detected in prostate basal epithelial cells. Its expression was absent in the majority of PCa specimens but present in a subset of NEPCa. Additionally, we evaluated the mRNA levels of ten PKM isoforms that express exon 9 (PKM1-like) or exon 10 (PKM2-like). Some of these isoforms showed notable expression levels in PCa cell lines and human PCa specimens. These findings lay the groundwork for understanding PKMs role in PCa carcinogenesis and NEPCa progression. The distinct expression pattern of PKM isoforms in different PCa subtypes may offer insights into potential therapeutic strategies for treating PCa.

cancer biology↗

bioRxiv2023

Loss of PAX6 alters the excitatory/inhibitory neuronal ratio in human cerebral organoids

The transcription factor PAX6 is a crucial regulator of multiple aspects of embryonic forebrain development. It has well-established roles in the regulation of excitatory and inhibitory neuron development in the embryonic cortex in mice but PAX6s roles during human forebrain development are less well understood. Using human cerebral organoids, we investigated PAX6s roles in human neurodevelopment. Homozygous PAX6 mutant (PAX6-/-) organoids were larger than controls and contained increased inhibitory cell types. Excitatory neurons were still generated in PAX6-/- organoids but they were less mature, and a subset showed dysregulated expression of inhibitory identity genes compared to PAX6+/+ controls. The inhibitory cells found in PAX6-/- organoids physically segregated from excitatory neurons and presented a distinct transcriptomic profile when compared to in vivo cortical inhibitory neurons. PAX6-/- organoids showed a dysregulated cellular response to PTN-PTPRZ1 signalling, which contributed to the observed increase in inhibitory neurons and the consequent altered excitatory to inhibitory neuronal ratio. Summary StatementHuman cerebral organoids lacking PAX6 expression show an altered excitatory to inhibitory neuronal ratio, concomitant with altered responses to intercellular PTN-PTPRZ1 signalling.

developmental biology↗

bioRxiv2022

Single cell analysis of senescent epithelia reveals targetable mechanisms promoting fibrosis

Progressive fibrosis and maladaptive organ repair result in significant morbidity and millions of premature deaths annually. Senescent cells accumulate with ageing and after injury and are implicated in organ fibrosis, but the mechanisms by which senescence influences repair are poorly understood. Using two murine models of injury and repair we show that obstructive injury generates senescent epithelia which persist after resolution of the original injury, promote ongoing fibrosis and impede adaptive repair. Depletion of senescent cells with ABT263 reduces fibrosis in reversed ureteric obstruction and after renal ischaemia-reperfusion injury. We validate these findings in humans, showing that senescence and fibrosis persist after relieved renal obstruction. We next characterise senescent epithelia in murine renal injury using single cell RNA-Seq. We extend our classification to human kidney and liver disease and identify conserved pro-fibrotic proteins which we validate in vitro and in human disease. We demonstrate that one such molecule, Protein Disulfide Isomerase Family A Member 3 (PDIA3), is essential for TGF-beta mediated fibroblast activation. Inhibition of PDIA3 in vivo significantly reduces kidney fibrosis during ongoing renal injury and as such represents a new potential therapeutic pathway. Analysis of the signalling pathways of senescent epithelia connects senescence to organ fibrosis, permitting rational design of anti-fibrotic therapies.

cell biology↗

bioRxiv2020

Exploratory polarization facilitates mating partner selection in Saccharomyces cerevisiae

Yeast decode pheromone gradients to locate mating partners, providing a model for chemotropism. How yeast polarize toward a single partner in crowded environments is unclear. Initially, cells often polarize in unproductive directions, but then they relocate the polarity site until two partners polarity sites align, whereupon the cells "commit" to each other by stabilizing polarity to promote fusion. Here we address the role of the early mobile polarity sites. We found that commitment by either partner failed if just one partner was defective in generating, orienting, or stabilizing its mobile polarity sites. Mobile polarity sites were enriched for pheromone receptors and G proteins, and we suggest that such sites engage in an exploratory search of the local pheromone landscape, stabilizing only when they detect elevated pheromone levels. Mobile polarity sites were also enriched for pheromone secretion factors, and simulations suggest that only focal secretion at polarity sites would produce high pheromone concentrations at the partners polarity site, triggering commitment.

cell biology↗

bioRxiv2019

SOX9 is required for kidney fibrosis and regulates NAV3 to control renal myofibroblast function in mice and humans

Renal fibrosis is a common endpoint for many chronic kidney diseases. Extracellular matrix (ECM) from myofibroblasts causes progressive scarring and organ failure. The mechanisms underlying fibrogenesis and how it is sustained are incompletely understood. Here, we show that the transcription factor, Sex determining region Y-box 9 (SOX9), is required for kidney fibrosis. From genome-wide analysis we identify Neuron navigator 3 (NAV3) downstream of SOX9. NAV3 was upregulated in kidney disease in patients and following renal injury in mice colocalised with SOX9. By establishing an in vitro model of renal pericyte transition to myofibroblast we demonstrated that NAV3 is required for multiple aspects of fibrogenesis including actin polymerization linked to cell migration and sustaining SOX9 and active YAP1 levels. In summary, our work discovers novel SOX9-NAV3-YAP1/SOX9 circuitry as a new mechanism to explain the progression of kidney fibrosis and points to NAV3 as a novel target for pharmacological intervention.

cell biology↗

bioRxiv2018

A macrophage-pericyte axis directs tissue restoration via Amphiregulin-induced TGFβ activation

The Epidermal Growth Factor Receptor ligand Amphiregulin has a well-documented role in the restoration of tissue homeostasis following injury; however, the mechanism by which Amphiregulin contributes to wound repair remains unknown. Here we show that Amphiregulin functions by releasing bio-active TGFb from latent complexes via integrin-v activation. Using acute injury models in two different tissues, we found that by inducing TGFb activation on mesenchymal stromal cells (aka pericytes), Amphiregulin induced their differentiation into myo-fibroblasts, thereby selectively contributing to the restoration of vascular barrier function within injured tissue. Furthermore, we identified macrophages as a critical source of Amphiregulin, revealing a direct effector mechanism by which these cells contribute to tissue restoration following acute injury. Combined, these observations expose a so far under-appreciated mechanism of how cells of the immune system selectively control the differentiation of tissue progenitor cells during tissue repair and inflammation.

immunology↗