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Grammenoudi, S.

Publications and source records attributed to Grammenoudi, S..

2 recordsLinked to original sources

Talin regulates steady-state tensional homeostasis to drive vascular morphodynamics and cancer

The mechanical properties of the extracellular environment emerge as critical regulators of cellular functions. Cell mechanotransduction is mainly studied in vitro at initial stages of cell adhesion and very little is known about the mechanoresponses of cells with established tensional dynamics, resembling cells embedded in tissues. Here, we provide in vivo evidence that talin-dependent cell-matrix adhesions are global regulators of vascular mechanics and establish talin as an essential and required mechanosensor in neovessels and already developed tumours. At the molecular level, we demonstrate that talin exploits alternative mechanisms to dynamically-adjust the mechanical integrity of endothelial cells. Our mutational studies indicate a previously unknown role for the requirement of the talin-head in mechanosensing and demonstrate that the talin-head and the talin-rod alone are sufficient to maintain mechanical stability of endothelial cells. Overall, our results underpin the significance of mechanical signals in regulating vascular morphology in steady-state conditions and ultimately modulate cancer progression. Talin mechanosensing is required to maintain cell morphology and control developmental and tumour angiogenesis.

cell biology↗

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↗