Project description:Mechanosensitive ion channels have emerged as fundamental proteins in sensing extracellular matrix (ECM) mechanics. Among those, Piezo1 has been proposed as a key mechanosensor in cells. However, whether and how Piezo1 senses time-dependent ECM mechanical properties (i.e., viscoelasticity) remains unknown. To address this question, we combined an immortalised mesenchymal stem cell (MSC) line with adjustable Piezo1 expression with soft (0.4 kPa) and stiff (25 kPa) viscoelastic hydrogels with independently tuneable Young’s modulus and stress relaxation. Here, we propose that Piezo1 is an important sensor of stiffness at this range (25kPa) consistent with the molecular clutch model. By performing RNA sequencing (RNA-seq), we identified the transcriptomic phenotype of MSCs response to matrix viscoelasticity and Piezo1 activity, highlighting gene signatures that drive MSCs mechanobiology at this elasticity scale.
Project description:Mechanosensitive ion channels have emerged as fundamental proteins in sensing extracellular matrix (ECM) mechanics. Among those, Piezo1 has been proposed as a key mechanosensor in cells. However, whether and how Piezo1 senses time-dependent ECM mechanical properties (i.e., viscoelasticity) remains unknown. To address this question, we combined an immortalised mesenchymal stem cell (MSC) line with adjustable Piezo1 expression with soft (400 Pa) and stiff (25 kPa) viscoelastic hydrogels with independently tuneable Young’s modulus and stress relaxation. Here, we propose that Piezo1 is an important sensor of stiffness at this range (25kPa) consistent with the molecular clutch model. By performing RNA sequencing (RNA-seq), we identified the transcriptomic phenotype of MSCs response to matrix viscoelasticity and Piezo1 activity, highlighting gene signatures that drive MSCs mechanobiology at this elasticity scale.
Project description:Mechanosensitive ion channels have emerged as fundamental proteins in sensing extracellular matrix (ECM) mechanics. Among those, Piezo1 has been proposed as a key mechanosensor in cells. However, whether and how Piezo1 senses time-dependent ECM mechanical properties (i.e., viscoelasticity) remains unknown. To address this question, we combined an immortalised mesenchymal stem cell (MSC) line with adjustable Piezo1 expression with soft (400 Pa) and stiff (25 kPa) viscoelastic hydrogels with independently tuneable Young’s modulus and stress relaxation. Here, we propose that Piezo1 is an important sensor of stiffness at this range (25kPa) consistent with the molecular clutch model. By performing RNA sequencing (RNA-seq), we identified the transcriptomic phenotype of MSCs response to matrix viscoelasticity and Piezo1 activity, highlighting gene signatures that drive MSCs mechanobiology at this elasticity scale.
Project description:The tumour microenvironment is a critical element involved in tumour progression and responsiveness to therapies. Using functionalized tunable stiffness hydrogel, mimicking the mechanical properties of healthy and tumour tissues, we explore how the stiffness of the microenvironment can influence cancer cells by generating RNA-seq transcriptional profiles of 4T1 mouse breast cancer cells cultured on soft vs stiff polyacrylamide hydrogels for 24 hours.
Project description:Metastatic breast cancer cells disseminate to organs with a soft microenvironment. Whether and how tissue mechanical properties influence their response to treatment remains unclear. Here we found that a soft ECM empowers redox homeostasis. Cells cultured on a soft ECM display increased peri-mitochondrial F-actin promoted by Spire1C and Arp2/3 nucleation factors, and increased DRP1- and MIEF1/2-dependent mitochondrial fission. Changes in mitochondrial dynamics lead to increased mtROS production and activate the NRF2 antioxidant transcriptional response, including increased cystine uptake and glutathione metabolism. This retrograde response endows cells with resistance to oxidative stress and ROS-dependent chemotherapy drugs. This is relevant in a mouse model of metastatic breast cancer cells dormant in the lung soft tissue, where inhibition of DRP1 and NRF2 restored cisplatin sensitivity and prevented disseminated cancer cell awakening. We propose that targeting this mitochondrial dynamics- and redox-based mechanotransduction pathway could open new avenues to prevent metastatic relapse.
Project description:Hippocampal rat neurons have been cultured on very soft (100 Pa) and stiff (10 kPa) hydrogels for 7 days. On DIV7, the RNA has been extracted and sequenced. The goal of this experiment is to understand why neurons mature more quickly on soft gels compared to stiff gels.
Project description:Human mesenchymal stem cells (MSCs) have demonstrated promise when delivered to damaged tissue or tissue defects for their cytokine secretion and inflammation modulation behaviors that can promote repair. Insulin-like growth factor 1 (IGF-1) has been shown to augment MSCs’ viability and survival and promote their secretion of cytokines that signal to endogenous cells, in the treatment of myocardial infarction, wound healing, and age-related diseases. Biomaterial cell carriers can be functionalized with growth factor-mimetic peptides to enhance MSC function while promoting cell retention and minimizing off-target effects seen with direct administration of soluble growth factors. Here, we functionalized alginate hydrogels with three distinct IGF-1 peptide mimetics and the integrin-binding peptide, cyclic RGD. One IGF-1 peptide mimetic (IGM-3) was found to activate Akt signaling and support survival of serum-deprived MSCs. MSCs encapsulated in alginate hydrogels that presented both IGM-3 and cRGD showed a significant reduction in pro-inflammatory cytokine secretion when challenged with interleukin-1β. Finally, MSCs cultured within the cRGD/IGM-3 hydrogels were able to blunt pro-inflammatory gene expression of human primary cells from degenerated intervertebral discs. These studies indicate the potential to leverage cell adhesive and IGF-1 growth factor peptide mimetics together to control therapeutic secretory behavior of MSCs.