Biology subjects

Piotrowski, A.

Publications and source records attributed to Piotrowski, A..

6 recordsLinked to original sources

bioRxiv2026

Spatial Transcriptomics of TNBC tumours and corresponding lymph node metastasis reveals immune hubs driven by TNF/NF-κB signalling of TMSB4X and CD74 expressing cells.

PurposeLymph node metastasis is a critical prognostic factor in triple-negative breast cancer (TNBC), but the spatial organization of signalling networks driving metastatic colonization and persistence remains poorly defined. Understanding these networks may reveal therapeutic vulnerabilities in metastatic TNBC. MethodsWe applied Visium spatial transcriptomics to paired primary tumours and lymph node metastases from four TNBC patients. Spatial gene expression profiles were analysed using trajectory inference, cell-type deconvolution, and cell-cell communication mapping. Results were validated in independent single-cell RNA sequencing datasets from TNBC tumours and lymph node metastases. ResultsTMSB4X and CD74 emerged as key drivers of metastasis-associated transcriptional programs, defining spatially distinct immune communication hubs enriched in myeloid, stromal, and endothelial cells. These hubs preferentially activated NF-{kappa}B/TNF signalling alongside PI3K-Akt and Rap1 pathways. In primary tumours, NF-{kappa}B/TNF signalling was confined to localized immune hubs, whereas lymph node metastases exhibited widespread signalling across cellular compartments with additional IL-1 pathway activation. This spatial rewiring coincided with endothelial cells assuming central coordinating roles in metastatic lesions. Independent validation confirmed myeloid-endothelial crosstalk as a conserved feature of TNBC, with TMSB4X-CD74 programs enriched in clinically relevant immune and vascular subpopulations. ConclusionTNBC lymph node metastases display spatially expanded inflammatory networks centred on TMSB4X-CD74 immune hubs. Metastatic progression involves coordinated myeloid-endothelial signalling, suggesting these pathways as potential biomarkers and therapeutic targets. Disrupting inflammatory and vascular communication networks may offer a strategy to prevent metastatic persistence and overcome therapy resistance in TNBC.

molecular biology↗

bioRxiv2025

The effect of cold ischemia time on hypoxia, EMT, and apoptosis pathways in normal colon mucosa

Cold ischemia time (CIT), the interval between tissue excision and preservation, is a critical preanalytical variable that profoundly impacts gene expression profiles. Variability in CIT can lead to inconsistent transcriptomic results, making study interpretation challenging and undermining reproducibility in biomedical research. Our study aimed to evaluate the impact of CIT on the expression of cancer-related genes, particularly these involved in hypoxia, apoptosis, and epithelial-to-mesenchymal transition (EMT). We performed RNA sequencing on 54 normal colon mucosa samples from nine patients undergoing colorectal cancer surgeries, freezing samples at predefined intervals ranging from 0 to 60 minutes. A total of 44 differentially expressed genes (DEGs) (p < 0.05) were identified when comparing samples frozen immediately (T0) with those frozen after 60 minutes (T5). These DEGs were further analyzed through functional and pathway enrichment analyses and weighted gene coexpression network analysis (WGCNA). The enrichment analysis revealed significant alterations in pathways associated with apoptosis, hypoxia, EMT, and cancer progression, including p53 and HIF-1 signaling. WGCNA highlighted two co-expressed gene modules: ME2, which showed downregulation of apoptosis-related genes, and ME4, linked to apoptosis and cellular metabolism. Our findings highlight CIT as a critical preanalytical variable, showing that prolonged ischemia can induce transcriptomic changes that may mimic malignancy, and potentially confound research outcomes. To minimize such effects, we recommend keeping CIT under 45-60 minutes.

cancer biology↗

bioRxiv2024

Development of a small-molecule epigenetic regenerative therapy. Subcutaneous administration of alginate formulations with high loads of zebularine and retinoic acid promotes tissue growth, vascularization and innervation and induces extensive epigenetic repatterning

Recently, zebularine, a small-molecule epigenetic inhibitor and retinoic acid, acting as a transcriptional activator, have been found to induce tissue regeneration. In this study, the pro-regenerative properties of zebularine and retinoic acid were combined with the potential of the alginate carrier to expand its therapeutic possibilities. Alginate formulations of zebularine and retinoic acid were developed for subcutaneous administration to mice. Hydrophilic zebularine formed a homogenous formulation with extreme drug loadings reaching 240 mg of zebularine per 1 ml of 2% sodium alginate, while hydrophobic retinoic acid, 0.8 mg/ml, dispersed as fine crystals. Cell culture tests exhibited no significant cytotoxicity of the alginate formulations. Subcutaneous administration of zebularine and retinoic acid in 2% sodium alginate promoted regenerative responses in a mouse model of ear pinna punch wound mice involving the restoration of tissue architecture, nerve and vessel growth, and extensive epigenetic and transcriptional repatterning with no adverse effects observed in the animals. Significant trancriptomic responses to the epigenetic treatment included the induction of epithelium development genes contrasted with the downregulation of muscle development genes on day 7 post-injury. Among the remarkable changes in global gene methylation are those in neurodevelopmental genes. In vitro studies showed rapid zebularine but no retinoic acid discharge from the alginate formulations. Live ultrasound imaging demonstrated gradual absorption of the subcutaneously injected alginate formulations, which may explain the in vivo activity of retinoic acid following subcutaneous administration. Effective induction of tissue regeneration together with a high safety profile and of the subcutaneously administered pro-regenerative alginate formulations opens the way to testing further regenerative therapies for hard-to-reach lesions.

bioengineering↗

bioRxiv2024

Prelude to Malignancy: A Gene Expression Signature in Normal Mammary Gland from Breast Cancer Patients Suggests Pre-tumorous Alterations and Is Associated with Adverse Outcomes

Despite advances in early detection and treatment strategies, breast cancer recurrence and mortality remain a significant health issue. Recent insights suggest the prognostic potential of microscopically healthy mammary gland, in the vicinity of the breast lesion. Nonetheless, a comprehensive understanding of the gene expression profiles in these tissues and their relationship to patient outcomes is still missing. Furthermore, the increasing trend towards breast-conserving surgery may inadvertently lead to the retention of existing cancer-predisposing mutations within the normal mammary gland. This study assessed the transcriptomic profiles of 242 samples from 83 breast cancer patients with unfavorable outcomes, including paired uninvolved mammary gland samples collected at varying distances from primary lesions. As a reference, control samples from 53 mammoplasty individuals without cancer history were studied. A custom panel of 634 genes linked to breast cancer progression and metastasis was employed for expression profiling, followed by whole-transcriptome verification experiments and statistical analyses to discern molecular signatures and their clinical relevance. A distinct gene expression signature was identified in uninvolved mammary gland samples, featuring key cellular components encoding keratins, CDH1, CDH3, EPCAM cell adhesion proteins, matrix metallopeptidases, oncogenes, tumor suppressors, along with crucial genes (FOXA1, RAB25, NRG1, SPDEF, TRIM29, and GABRP) having dual roles in cancer. Enrichment analyses revealed disruptions in epithelial integrity, cell adhesion, and estrogen signaling. This signature, named KAOS for Keratin-Adhesion-Oncogenes-Suppressors, was significantly associated with reduced tumor size but increased mortality rates. Integrating molecular assessment of non-malignant mammary tissue into disease management could enhance survival prediction and facilitate personalized patient care.

genomics↗

bioRxiv2022

Size matters - the impact of nucleus size on results from spatial transcriptomics

Visium Spatial Gene Expression (ST) is a method combining histological spatial information with transcriptomics profiles directly from tissue sections. The use of spatial information has made it possible to discover novel modes of gene expression regulations. However, in the ST experiment, the nucleus size of cells may exceed the thickness of a tissue slice. This may, in turn, negatively affect comprehensive capturing the transcriptomics profile in a single slice, especially for tissues having large differences in the size of nuclei. Here, we defined the effect of Consecutive Slices Data Integration (CSDI) on results from spatial transcriptomic study of human postmortem brains. CSDI can be applied to investigate consecutive sections studied with ST in the human cerebral cortex, avoiding misinterpretation of spot clustering and annotation, increasing accuracy of cell recognition as well as improvement in uncovering the layers of grey matter in the human brain.

bioinformatics↗

bioRxiv2019

Loss of Y in leukocytes, dysregulation of autosomal immune genes and disease risks

Mosaic loss of chromosome Y (LOY) in leukocytes has been associated with many diseases, yet it remains unclear whether this form of clonal mosaicism exerts a direct physiological effect. Here we perform single-cell and bulk RNA sequencing in leukocytes, observing considerable variation in the rate of LOY across individuals, cell types and disease state. Cells with LOY demonstrated a profound degree of transcriptional dysregulation impacting [~]500 autosomal genes. These genes are preferentially involved in immune functions but also encode proteins with roles in other diverse biological processes. Our findings highlight a surprisingly broad role for chromosome Y challenging the view of it as a "genetic wasteland". Furthermore, they support the hypothesis that altered immune function in leukocytes is a mechanism directly linking LOY to disease.

immunology↗