Biology subjects

Koliaraki, V.

Publications and source records attributed to Koliaraki, V..

4 recordsLinked to original sources

bioRxiv2025

High-resolution integrative analysis allows characterization and spatial annotation of normal and cancer-associated colon fibroblasts

Fibroblasts represent key regulators of colon homeostasis, and cancer-associated fibroblasts (CAFs) play pivotal roles in colorectal cancer (CRC). Despite their critical influence, a consensus view of adult human colon fibroblast and CRC CAF heterogeneity, spatial organization, and developmental trajectories is currently lacking. Here, we address this gap by performing a comprehensive characterization of colonic fibroblasts and CRC CAFs. Using large-scale integration of single-cell RNA-sequencing datasets from normal colon and CRC we mapped the fibroblast subpopulations. Spatial transcriptomics, immunohistochemistry, and in situ hybridization were used for validation and computational analyses to predict developmental trajectories and transcription factors underlying CAF activation. Subepithelial myofibroblasts (SEMFs), mucosa-associated fibroblasts (MAFs), and submucosa-associated fibroblasts (SAFs) were identified as the main colon fibroblast subtypes, and in mice, further divided into location-based subclusters. We also identified a novel colon fibroblast subset: muscle-embedded interstitial fibroblasts (MIFs). CRCs contained normal fibroblasts as well as four cancer-specific CAF populations: inflammatory CAFs (iCAFs), matrix CAFs (mCAFs), and two precursor CAF (preCAF) subtypes. Our data suggested that iCAFs originate from SEMFs through a preCAF1 intermediate phenotype, while mCAFs derive from SAFs/MIFs via preCAF2s. Transcription factors PRRX1, MAFB, and TWIST1 were uncovered as potential regulators of CAF identity and CTHRC1 was identified as a specific and sensitive pan-CAF marker in CRC. Our study presents a detailed framework for understanding colon fibroblast and CRC CAF heterogeneity. This work lays the groundwork for future research into the roles and potential therapeutic relevance of different CRC CAF subsets.

cancer biology↗

bioRxiv2025

Notch3 regulates pericyte phenotypic plasticity in colorectal cancer

Pericytes undergo phenotypic alterations that influence cancer progression, yet the molecular mechanisms governing these changes remain poorly understood. Here, we investigated the role of Notch3 signaling in pericyte phenotype and functions in colorectal cancer (CRC). Using lineage tracing approaches, we showed that tumor pericytes originate from normal tissue-resident pericytes, which proliferate inside tumors. In vivo genetic manipulation revealed that Notch3 pathway activation promotes pericyte proliferation, while suppressing contractile protein expression, and leads to increased endothelial cell proliferation. In contrast, Notch3 deletion leads to reduced endothelial proliferation and a significant decrease in. This effect is associated with a shift toward a contractile phenotype. Single-cell RNA sequencing analysis uncovered significant pericyte heterogeneity in both mouse colitis-associated cancer and human CRC. It specifically identified functionally distinct subpopulations characterized by differential Notch3 activity, which supported our in vivo and in vitro findings. Our results establish Notch3 as a key regulator of pericyte phenotypic plasticity in CRC and suggest that targeting this pathway could represent a promising strategy for improving therapeutic outcomes through vascular normalization.

cancer biology↗

bioRxiv2023

Cellular complexity and crosstalk in murine TNF-dependent ileitis: Different fibroblast subsets propel spatially defined ileal inflammation through TNFR1 signalling

Crohns disease represents a persistent inflammatory disorder primarily affecting the terminal ileum. Through the application of single-cell RNA sequencing, we unveil the intricate cellular complexities within murine TNF-dependent ileitis, developing in Tnf{Delta}ARE mice. Detailed immune cell analysis highlights B cell expansion, T cell effector reprogramming, and macrophage lineage shifts during inflammation. Focusing on stromal cells, we reveal a strong pro-inflammatory character, acquired by all fibroblast subsets, which exhibit complex communication patterns with the infiltrating immune and surrounding stromal cells. Interestingly, we identify that Tnf{Delta}ARE-induced ileitis is initiated in the lamina propria via TNFR1 pathway activation in villus-associated fibroblasts (Telocytes and Pdgfralow cells). Furthermore, we unveil separate spatial subsets of fibroblasts acting as exclusive responders to TNF, each orchestrating inflammation in different intestinal layers. Additionally, manipulating the Tnfrsf1a gene exclusively in fibroblast subsets suggests that inflammation is initiated by telocytes and Pdgfralow cells, while trophocytes drive its progression. This introduces novel evidence of spatial regulation of inflammation by fibroblast subsets, inciting and advancing disease in different layers of the gut. These findings underscore the pivotal role of fibroblasts in the inception and advancement of ileitis, proposing that targeting different fibroblast populations could impede the disease development and chronicity of inflammation.

cell biology↗

bioRxiv2021

Col6a1+/CD201+ telocytes regulate intestinal morphogenesis and homeostasis

Intestinal mesenchymal cells encompass multiple subsets, whose origins, functions, and pathophysiological importance are still not clear. Here, we used the Col6a1Cre mouse, which targets telocytes and perivascular cells that can be further distinguished by the combination of the CD201, PDGFR and SMA markers. Developmental studies revealed that the Col6a1Cre mouse also targets mesenchymal aggregates that are crucial for intestinal morphogenesis and patterning, suggesting an ontogenic relationship between them and homeostatic telocytes. Cell depletion experiments in adulthood showed that Col6a1+/CD201+ mesenchymal cells regulate homeostatic enteroendocrine cell differentiation and epithelial proliferation. During acute colitis, they expressed an inflammatory and extracellular matrix remodeling gene signature, but they also retained their properties and topology. Notably, both in homeostasis and tissue regeneration, they were dispensable for normal organ architecture, while CD34+ mesenchymal cells expanded, localised at the top of the crypts and showed increased expression of villous-associated morphogenetic factors, providing thus evidence for the plasticity potential of distinct mesenchymal populations in the intestine. Our results provide a comprehensive analysis of the identities, origin, and functional significance of distinct mesenchymal populations in the intestine.

cell biology↗