Biology subjects

Ribas, C.

Publications and source records attributed to Ribas, C..

3 recordsLinked to original sources

bioRxiv2025

Loss of Gαq reshapes key fibroblast traits and drives matrix remodeling and aggressive progression of oral cancer tumors

Head and neck squamous cell carcinoma (HNSCC) is a highly aggressive cancer, with limited therapeutic options and a high mortality rate, primarily due to metastasis and recurrence. Tumor-stroma interactions, and namely cancer-associated fibroblasts (CAFs), are pivotal in shaping HNSCC progression. CAFs remodel the extracellular matrix (ECM) and secrete factors and vesicles that promote tumor growth and metastasis. The interplay between autophagy and endosomal/exosomal pathways has been suggested to regulate cellular secretory functions, but their potential involvement in HNSCC progression remains poorly understood. Since we have recently uncovered Gq as a key modulator of autophagy, we have investigated the impact of Gq loss on fibroblast functionality and on its crosstalk with oral HNSCC cells. We report that the absence of Gq rewires murine embryonic fibroblasts towards CAF-like traits, leading to an increased pro-tumorigenic capacity of co-cultured human oral cancer cells through enhanced collagen I deposition and ECM remodeling. Strikingly, fibroblasts lacking Gq display a shift in the balance of intracellular trafficking, degradative and secretory pathways. Exosomes released from Gq-deficient fibroblasts show a marked enrichment in tumor-growth factor receptors and can facilitate aberrant tumor growth of HNSCC cells. Gq-silenced fibroblasts promote the formation of "railroad-tracks" structures around HNSCC cells, enhancing their migratory and invasive capabilities both in vitro and in vivo, and reduced Gq expression in human HNSCC CAFs correlates with enhanced tumor progression. Overall, our data put forward Gq as a key regulator of the HNSCC tumor microenvironment by modulating fibroblast plasticity and functionality.

cancer biology↗

bioRxiv2024

Harnessing homeostatically active RhoC at cell junctions preserves human endothelial barrier function during inflammation

Rho GTPases are molecular targets of bacterial toxins that modulate their enzymatic activity. RhoA, RhoB and RhoC are almost identical and play critical roles in generating actomyosin-mediated contractile forces that cause endothelial hyperpermeability during inflammation. Searching for new treatments to modulate endothelial integrity, we demonstrate that the specific and simultaneous activation of these three Rho GTPases with a chimeric recombinant toxin does not induce cell contraction but enhances homeostatic endothelial barrier function, increases reticular adherens junctions and preserves the microvascular endothelium in response to pathological inflammatory challenges in vitro and in vivo. This pro-barrier effect is specifically mediated by RhoC, whose activity is increased by cell confluence. The uniqueness of RhoC relies on an arginine 188 within its hypervariable region that determines its junctional localization, high homeostatic activity, and barrier-protective function. Quantitative proteomics revealed that RhoC regulates the expression of myosin light chain proteins and junction-stabilizing actomyosin. Thus, harnessing the activity of RhoC represents a potential therapy for strengthening endothelial barriers during pathological inflammation.

cell biology↗

bioRxiv2024

The G-Protein Couple Receptor Kinase 2 (GRK2) Orchestrates Hair Follicle Homeostasis

Tightly regulated cell-cell and cell-niche intercommunications via intertwined signaling networks are involved in maintaining normal hair follicle (HF) homeostasis, cycling and cell fate determination. However, knowledge of specific mechanisms by which hair loss takes place under pathological situations is needed. Using a keratinocyte-specific knockout mouse model, we uncover that the G-protein-coupled receptor kinase 2 (GRK2) signaling node plays a key role in HF homeostasis. Epidermal GRK2 ablation causes alterations during anagen induction, giving rise to abnormal cyst-like structures. HF-linked cysts display aberrant growth and differentiation patterns as well as lineage infidelity, displaying features of abortive HFs unable to fully acquire canonical hallmarks. Cysts triggered by GRK2 deletion displace the dermal papilla away from the bulge and promote irreversible changes in HF stem cell architecture, leading to bulge destruction and hair loss. Our data provide unforeseen roles of GRK2 in epidermal physiology and uncover mechanisms linking dystrophic follicular cysts formation with hair loss, with potential connections to pathogenic processes operating in immune-mediated alopecias.

cell biology↗