Biology subjects

Clements, M.

Publications and source records attributed to Clements, M..

7 recordsLinked to original sources

bioRxiv2026

PDLP5 regulates aquaporin-mediated hydrogen peroxide transport in Arabidopsis

Aquaporins facilitate the diffusion of water and small neutral molecules, including hydrogen peroxide (H2O2). In Arabidopsis, plasma membrane intrinsic proteins (PIPs, members of aquaporins) mediate H2O2 transport; however, the regulatory mechanisms governing their activity are not fully understood. Here, we show that plasmodesmata-located protein 5 (PDLP5), a key regulator of plasmodesmal function, negatively regulates PIP-dependent H2O2 transport. PDLP5 forms complexes with PIPs, with its extracellular domain predicted to associate with the extracellular face of the channel. PDLP5 overexpression suppresses H2O2 uptake and confers reduced sensitivity to H2O2-induced root growth inhibition, whereas pdlp5 mutants display the opposite phenotype. We further identify PIP2;5 as a critical component of PDLP5-mediated regulation. These findings reveal an extracellular mechanism for modulating aquaporin function, expanding current models of channel regulation in plants.

plant biology↗

bioRxiv2025

Microenvironmental TGF-β is an early driver of NF1-associated tumour formation

Neurofibromatosis Type 1 (NF1) is a common tumour predisposition syndrome characterised by neurofibromas - Nf1-/- Schwann cell (SC)-derived tumours of peripheral nerves. We and others have shown that Nf1 loss in SCs is insufficient for neurofibroma formation but cooperates with an injury microenvironment to form tumours, but the mechanisms remained unknown. Here, we identify macrophage-secreted TGF-{beta} as the microenvironmental injury signal that is essential for tumourigenesis. Analysis of the earliest stages of neurofibroma formation showed that tumours arise from a population of Nf1-/- SCs that escape the regenerating nerve shortly after injury. Here, they reside in a distinct microenvironment conducive for tumourigenesis, where TGF-{beta} disrupts SC/axonal interactions and SC re-differentiation. Pharmacological inhibition of TGF-{beta} for a short therapeutic window during this early stage inhibited tumour formation, highlighting the potential to normalise Nf1-/- SCs and identifying TGF-{beta} as a potential therapeutic target to both treat and prevent neurofibroma formation.

cell biology↗

bioRxiv2023

Ageing-related defects in macrophage function are driven by MYC and USF1 transcriptional programmes

Macrophages are central innate immune cells whose function declines with age. The molecular mechanisms underlying age-related immunity changes remain poorly understood, particularly in human macrophages. We report a substantial reduction in phagocytosis, migration and chemotaxis in human monocyte-derived macrophages (MDMs) from older (>50 years) compared with younger (18-30 years) donors, alongside downregulation of transcription factors MYC and USF1 with age. In MDMs from young donors, knockdown of MYC or USF1 decreased phagocytosis and chemotaxis and altered expression of genes associated with these functions, as well as adhesion and extracellular matrix remodelling. A concordant dysregulation of MYC and USF1 target genes was also seen in MDMs from older donors. Furthermore, older age and loss of either MYC or USF1 in MDMs led to an increased cell size, altered morphology and reduced actin content. Together, these results define MYC and USF1 as key drivers of MDM age-related functional decline and identify downstream targets to improve macrophage function in ageing.

immunology↗

bioRxiv2022

Diet suppresses tumour initiation by maintaining quiescence of mutation-bearing neural stem cells

Glioblastoma is thought to originate from neural stem cells (NSCs) of the subventricular zone that acquire genetic alterations. In the adult brain, NSCs are largely quiescent, suggesting that deregulation of quiescence maintenance may be a pre-requisite for tumour initiation. Although inactivation of the tumour suppressor p53 is a frequent event in gliomagenesis, whether, or how, it affects quiescent NSCs (qNSCs) remains unclear. Here we show that p53 maintains quiescence by inducing fatty acid oxidation (FAO) and that acute p53 deletion in qNSCs results in their premature activation to a proliferative state. Mechanistically, this occurs through direct transcriptional induction of PPARGC1a, which in turn activates PPAR to upregulate FAO genes. Strikingly, dietary supplementation with fish oil containing omega-3 fatty acids, natural PPAR ligands, fully restores quiescence of p53-deficient NSCs and delays tumour initiation in a glioblastoma mouse model. Thus, diet can silence glioblastoma driver mutations, with important implications for cancer prevention.

cancer biology↗

bioRxiv2021

Small molecule allosteric inhibitors of RORγt block Th17-dependent inflammation and associated gene expression in vivo.

Retinoic acid receptor-related orphan nuclear receptor (ROR) {gamma}t is a member of the RORC nuclear hormone receptor family of transcription factors. ROR{gamma}t functions as a critical regulator of thymopoiesis and immune responses. ROR{gamma}t is expressed in multiple immune cell populations including Th17 cells, where its primary function is regulation of immune responses to bacteria and fungi through IL-17A production. However, excessive IL-17A production has been linked to numerous autoimmune diseases. Moreover, Th17 cells have been shown to elicit both pro- and anti-tumor effects. Thus, modulation of the ROR{gamma}t/IL-17A axis may represent an attractive therapeutic target for the treatment of autoimmune disorders and some cancers. Herein we report the design, synthesis and characterization of three selective allosteric ROR{gamma}t inhibitors in preclinical models of inflammation and tumor growth. We demonstrate that these compounds can inhibit Th17 differentiation and maintenance in vitro and Th17-dependent inflammation and associated gene expression in vivo, in a dose-dependent manner. Finally, ROR{gamma}t inhibitors were shown to inhibit tumor formation in pancreatic ductal adenocarcinoma (PDAC) organoids.

immunology↗

bioRxiv2021

An agnostic study of associations between ABO and RhD blood group and phenome-wide disease risk

There are multiple known associations between the ABO and RhD blood groups and disease. However, no systematic population-based studies elucidating associations between a large number of disease states and blood group have been conducted. Using SCANDAT3-S, a comprehensive nationwide blood donation-transfusion database, we modelled outcomes for 1,217 disease categories including 70 million person-years of follow-up, accruing from 5.1 million unique individuals. We discovered 49 and 1 associations between a disease and ABO and RhD blood group, respectively, after adjustment for multiple testing. We identified new associations such as kidney stones and blood group B as compared to O. We also expanded previous knowledge on other associations such as pregnancy-induced hypertension and blood group A and AB as compared to O and RhD positive as compared to negative. Our findings generate strong further support for previously known associations, but also indicate new interesting relations.

physiology↗

bioRxiv2018

A natural history model for planning prostate cancer testing: calibration and validation using Swedish registry data

Recent prostate cancer screening trials have given conflicting results and it is unclear how to reduce prostate cancer mortality while minimising overdiagnosis and overtreatment. Prostate cancer testing is a partially observable process, and planning for testing requires either extrapolation from randomised controlled trials or, more flexibly, modelling of the cancer natural history.\n\nAn existing US prostate cancer natural history model (Gulati et al, Biostatistics 2010;11:707-719) did not model for differences in survival between Gleason 6 and 7 cancers and predicted too few Gleason 7 cancers for contemporary Sweden. We re-implemented and re-calibrated the US model to Sweden. We extended the model to more finely describe the disease states, their time to biopsy-detectable cancer and prostate cancer survival. We first calibrated the model to the incidence rate ratio observed in the European Randomised Study of Screening for Prostate Cancer (ERSPC) together with age-specific cancer staging observed in the Stockholm PSA (prostate-specific antigen) and Biopsy Register; we then calibrated age-specific survival by disease states under contemporary testing and treatment using the Swedish National Prostate Cancer Register.\n\nAfter calibration, we were able to closely match observed prostate cancer incidence trends in Sweden. Assuming that patients detected at an earlier stage by screening receive a commensurate survival improvement, we find that the calibrated model replicates the observed mortality reduction in a simulation of ERSPC.\n\nUsing the resulting model, we predicted incidence and mortality following the introduction of regular testing. Compared with a model of the current testing pattern, organised 8 yearly testing for men aged 55-69 years was predicted to reduce prostate cancer incidence by 0.11% with no increase in the mortality rate. The model is open source and suitable for planning for effective prostate cancer screening into the future.\n\nAuthor summaryA naive perspective is that cancer screening is simple: people are screened, some cancers are detected early, and cancer mortality rates decline. However, the mathematics for screening becomes difficult quickly, it is hard to infer causation from observational data, and even large randomised screening studies provide limited evidence. Simulations are therefore important for planning cancer screening.\n\nWe found an older US prostate cancer natural history model to be poorly suited for contemporary Sweden. We therefore re-implemented and re-calibrated the US model using data from Swedish registries.\n\nOur revised model, the Stockholm \"Prostata\" model, provides predictions similar to those observed in the detailed Swedish registers on prostate cancer incidence and mortality. By modelling the mechanisms of the screening effect, we can predict the benefits and harms under a range of screening interventions.

epidemiology↗