Biology subjects

Walters, S.

Publications and source records attributed to Walters, S..

5 recordsLinked to original sources

bioRxiv2025

A systemic clock brake: Period1 stabilizes the circadian network under environmental stress

Precise alignment between internal circadian clocks and environmental light cycles is essential for physiological homeostasis and survival. However, the molecular mechanisms that preserve this synchrony across central and peripheral tissues remain poorly defined. Here, we uncover an unexpected role for the core clock gene Period1 (Per1) as a systemic modulator of circadian stability, regulating light-induced re-entrainment across the brain and body. In Per1-deficient mice, we show that loss of Per1 accelerates clock realignment, influencing transcriptomic, metabolic, hormonal, and behavioral indicators of circadian realignment across multiple organ systems, including the suprachiasmatic nucleus (SCN) and peripheral tissues such as the liver, adipose tissue, and adrenal glands. Notably, this accelerated adaptation confers protection against jetlag-induced sleep disturbances, weight gain, and metabolic imbalance, underscoring a systemic role for Per1 in maintaining circadian network stability. Mechanistically, unbiased spatial transcriptomics identified reduced expression of the arginine vasopressin (AVP), a key neuropeptide mediating SCN intercellular coupling, as the driver of circadian network instability. Weakened SCN synchrony permits enhanced flexibility of peripheral oscillator responses, expediting whole-body adaptation to shifted light-dark schedules. These findings position Per1 as a critical regulator of circadian robustness, a buffer against light over-responsiveness, identifying a potential molecular target for mitigating circadian misalignment in contexts such as jetlag, shift work, and metabolic disease. TeaserWhat if beating jetlag was as simple as switching off a gene? Researchers show that disabling Per1, a core circadian regulator, accelerates body clock realignment and protects against sleep and metabolic disruption--highlighting new therapeutic possibilities for jetlag and shift work.

neuroscience↗

bioRxiv2023

Spatial transcriptomic analysis of Sonic Hedgehog Medulloblastoma identifies that the loss of heterogeneity and promotion of differentiation underlies the response to CDK4/6 inhibition

BackgroundMedulloblastoma (MB) is a malignant tumour of the cerebellum which can be classified into four major subgroups based on gene expression and genomic features. Single cell transcriptome studies have defined the cellular states underlying each MB subgroup, however the spatial organisation of these diverse cell states and how this impacts response to therapy remains to be determined. MethodsHere, we used spatially resolved transcriptomics to define the cellular diversity within a sonic hedgehog (SHH) patient-derived model of MB and identify how cells specific to a transcriptional state or spatial location are pivotal in responses to treatment with the CDK4/6 inhibitor, Palbociclib. We integrated spatial gene expression with histological annotation and single cell gene expression data from MB, developing a analysis strategy to spatially map cell type responses within the hybrid system of human and mouse cells and their interface within an intact brain tumour section. ResultsWe distinguish neoplastic and non-neoplastic cells within tumours and from the surrounding cerebellar tissue, further refining pathological annotation. We identify a regional response to Palbociclib, with reduced proliferation and induced neuronal differentiation in both treated tumours. Additionally, we resolve at a cellular resolution a distinct tumour interface where the tumour contacts neighbouring mouse brain tissue consisting of abundant astrocytes and microglia and continues to proliferate despite Palbociclib treatment. ConclusionsOur data highlight the power of using spatial transcriptomics to characterise the response of a tumour to a targeted therapy and provide further insights into the molecular and cellular basis underlying the response and resistance to CDK4/6 inhibitors in SHH MB.

genomics↗

bioRxiv2023

Benchmarking robust spatial transcriptomics approaches to capture the molecular landscape and pathological architecture of archived cancer tissues

AbtractsApplying spatial transcriptomics (ST) to explore a vast amount of formalin-fixed paraffin-embedded (FFPE) archival cancer tissues has been highly challenging due to several critical technical issues. In this work, we optimised ST protocols to generate unprecedented spatial gene expression data for FFPE skin cancer. Skin is among the most challenging tissue types for ST due to its fibrous structure and a high risk of RNAse contamination. We evaluated tissues collected from ten years to two years ago, spanning a range of tissue qualities and complexity. Technical replicates and multiple patient samples were assessed. Further, we integrated gene expression profiles with pathological information, revealing a new layer of molecular information. Such integration is powerful in cancer research and clinical applications. The data allowed us to detect the spatial expression of non-coding RNAs. Together, this work provides important technical perspectives to enable the applications of ST on archived cancer tissues.

pathology↗

bioRxiv2020

Spatial analysis of ligand-receptor interactions in skin cancer at genome-wide and single-cell resolution

The ability to study cancer-immune cell communication across the whole tumor section without tissue dissociation is needed for cancer immunotherapies, to understand molecular mechanisms and to discover potential druggable targets. In this work, we developed a powerful experimental and analytical toolbox to enable genome-wide scale discovery and targeted validation of cellular communication. We assessed the utilities of five sequencing and imaging technologies to study cancer tissue, including single-cell RNA sequencing and Spatial Transcriptomic (measuring over >20,000 genes), RNA In Situ Hybridization (multiplex 4-12 genes), digital droplet PCR, and Opal multiplex protein staining (4-9 proteins). To spatially integrate multimodal data, we developed a computational method called STRISH that can automatically scan across the whole tissue section for local expression of gene and/or protein markers to recapitulate an interaction landscape across the whole tissue. We evaluated the unique ability of this toolbox to discover and validate cell-cell interaction in situ through in-depth analysis of two types of cancer, basal cell carcinoma and squamous cell carcinoma, which account for over 70% of cancer cases. We expect that the approach described here will be widely applied to discover and validate ligand receptor interaction in different types of solid cancer tumors.

cancer biology↗

bioRxiv2020

A zebrafish functional genomics model to investigate the role of human A20 variants in vivo

Germline loss-of-function variation in TNFAIP3, encoding A20, has been implicated in a wide variety of autoinflammatory and autoimmune conditions, with acquired somatic missense mutations linked to cancer progression. Furthermore, human sequence data reveals that the A20 locus contains ~400 non-synonymous coding variants which are largely uncharacterised. The growing number of A20 coding variants with unknown function, but potential clinical impact, poses a challenge to traditional mouse-based approaches. Here we report the development of a novel functional genomics approach that utilises the new A20-deficient zebrafish (Danio rerio) model to investigate the impact of TNFAIP3 genetic variants in vivo. Similar to A20-deficient mice, A20-deficient zebrafish are hyper-responsive to inflammatory triggers and exhibit spontaneous early lethality. While ectopic addition of human A20 rescued A20-null zebrafish from lethality, missense mutations at two conserved A20 residues, S381A and C243Y reversed this protective effect. Ser381 represents a phosphorylation site important for enhancing A20 activity that is abrogated by its mutation to alanine, or by a C243Y mutation that associates with human autoimmune disease. These data reveal an evolutionarily conserved role for A20, but also demonstrate how a zebrafish functional genomics pipeline can be utilized to investigate the in vivo significance of medically relevant TNFAIP3 gene variants. This approach could be utilised to investigate genetic variation for other conserved genes.

genetics↗