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Paredes, J.

Publications and source records attributed to Paredes, J..

3 recordsLinked to original sources

Detergent-Free Decellularization Preserves the Structural and Biological Integrity of Murine Tendon

Tissue decellularization has demonstrated widespread applications across numerous organ systems for tissue engineering and regenerative medicine applications. Decellularized tissues are expected to retain structural and/or compositional features of the natural extracellular matrix (ECM), enabling investigation of biochemical factors and cell-ECM interactions that drive tissue homeostasis, healing, and disease. However, the dense collagenous tendon matrix has limited the efficacy of traditional decellularization strategies without the aid of harsh chemical detergents and/or physical agitation that disrupt tissue integrity and denature proteins involved in regulating cell behavior. Here, we adapted and established the advantages of a detergent-free decellularization method that relies on Latrunculin B actin destabilization, alternating hypertonic-hypotonic salt and water incubations, nuclease-assisted elimination of cellular material, and protease inhibitor supplementation under aseptic conditions. Compared with previous tendon decellularization studies, our method minimized collagen denaturation while adequately removing cells and preserving bulk tissue alignment and mechanical properties. Furthermore, we demonstrated that decellularized tendon ECM-derived coatings isolated from different mouse strains, injury states (i.e., naive and acutely injured/provisional), and anatomical sites harness distinct biochemical cues and robustly maintain tendon cell viability in vitro. Together, our work provides a simple and scalable decellularization method to facilitate mechanistic studies that will expand our fundamental understanding of tendon ECM and cell biology. Impact StatementIn this study, we present a decellularization method for tendon that does not rely on any detergents or physical processing techniques. We assessed the impact of detergent-free decellularization using tissue, cellular, and molecular level analyses and validated the preservation of tendon structural organization, collagen molecular integrity, and ECM-associated biological cues that are essential for studying physiological cell-ECM interactions. Lastly, we demonstrated the success of this method on healthy and injured tendon environments, across mouse strains, and for different types of tendons, illustrating the utility of this approach for isolating the contributions of biochemical cues within unique tendon ECM microenvironments.

bioengineering↗

Activation of the actin/MRTF-A/SRF signalling pathway in pre-malignant mammary epithelial cells by P-cadherin is essential for transformation

Alterations in the expression or function of cell adhesion molecules have been implicated in all steps of tumour progression. Among those, P-cadherin expression is highly enriched in basal-like breast cancer, a molecular subset of triple-negative breast carcinomas, playing a central role in inducing cancer cell self-renewal, as well as collective cell migration and invasion capacity. To decipher the P-cadherin-dependent signalling network, we generated a humanised P-cadherin fly model, establishing a clinically relevant platform for functional exploration of P-cadherin effectors in vivo. We report that actin nucleators, MRTF and SRF are main effectors of P-cadherin functional effects. In addition, we validated these findings in a human mammary epithelial cell line with conditional activation of the Src oncogene, which recapitulates molecular events taking place during cellular transformation. We show that prior to triggering the gain of malignant phenotypes, Src induces a transient increase in P-cadherin expression levels, which correlates with MRTF-A accumulation, its nuclear translocation and the upregulation of SRF target genes. Moreover, knocking down P-cadherin, or preventing Factin polymerization with Latrunculin A, impairs SRF transcriptional activity. Furthermore, blocking MRTF-A nuclear translocation with CCG-203971 hampers proliferation, selfrenewal and invasion. Thus, in addition to sustaining malignant phenotypes, P-cadherin can also play a major role in the very early stages of breast carcinogenesis by promoting a transient boost of MRTF-A/SRF signalling through actin regulation.

cancer biology↗

Epithelial-mesenchymal plasticity induced by discontinuous exposure to TGFβ1 promotes tumour growth

Transitions between epithelial and mesenchymal cellular states (EMT/MET) contribute to cancer progression. We hypothesize that EMT followed by MET promotes cell population heterogeneity favouring tumour growth. We developed an EMT model by on/off exposure of epithelial EpH4 cells (E-cells) to TGF{beta}1 that mimics phenotypic EMT (M-cells) and MET. We aimed at understanding whether phenotypic MET is accompanied by molecular and functional reversion back to epithelia, by using RNA sequencing, Immunofluorescence (IF), proliferation, wound healing, focus formation and mamosphere formation assays, as well as cell-xenografts in nude mice. Phenotypic reverted-epithelial cells (RE-cells), obtained after MET induction, presented pure epithelial morphology and proliferation rate resembling E-cells. However, RE transcriptomic profile and IF staining of epithelial and mesenchymal markers revealed a unique and heterogeneous mixture of cell-subpopulations, with high self-renewal ability fed by oxidative phosporylation. RE-cells heterogeneity is stably maintained for long periods after TGF{beta}1 removal, both in vitro and in large derived tumours in nude mice. Overall, we show that phenotypic reverted-epithelial cells (RE-cells) do not return to the molecular and functional epithelial state, present mesenchymal features related with aggressiveness and cellular heterogeneity that favour tumour growth in vivo. This work strengthens epithelial cells reprogramming and cellular heterogeneity fostered by inflammatory cues as a tumour-growth promoting factor in vivo.

cell biology↗