Project description:To investigate the influence of stiffness as a major Bruch's membrane characteristic on the RPE transcriptome and morphology. ARPE-19 cells were plated on soft or stiff polyacrylamide gels (PA gels) or standard tissue culture plastic (TCP). We then performed gene expression profiling analysis using data obtained from Next-generation sequencing of small RNAs of ARPE-19 cells cultured on 3 different biomechanical conditions.
Project description:To investigate the influence of stiffness as a major Bruch's membrane characteristic on the RPE transcriptome and morphology. ARPE-19 cells were plated on soft or stiff polyacrylamide gels (PA gels) or standard tissue culture plastic (TCP). We then performed gene expression profiling analysis using data obtained from Next-generation sequencing of small RNAs of ARPE-19 cells cultured on 3 different biomechanical conditions.
Project description:Treating recurrent GBM is a clinical challenge due to its highly resistant and aggressive nature. In order to develop new therapeutic targets for recurrent GBM a better understanding of its molecular landscape is necessary. Here we used a cellular model, developed in our lab which generates paired primary and recurrent samples from GBM cell lines and primary patient samples hence allowing us to compare the molecular differences between the two populations. Total RNA seq analysis of parent and recurrent population of two cell lines and one patient sample revealed a significant upregulation of Extracellular matrix interaction in recurrent population. Since matrix stiffness plays a pivotal role in cell-ECM interaction and downstream signaling, we developed a system that mimicked the brain like substrate stiffness by using collagen coated polyacrylamide-based substrate whose stiffness can be modified from normal brain (0.5kPa) to tumorigenic (10kPa). Using these substrates, we were able to capture the morphological and physiological differences between parent and recurrent GBM which were not evident on plastic surfaces (~1 GPa). On 0.5kPa, unlike circular parent cells, recurrent GBM cells showed two morphologies (circular and elongated). The recurrent cells growing on 0.5kPa also showed higher proliferation, invasion, migration and in-vivo tumorigenicity in orthotropic GBM mouse model, compared to parent cells. Furthermore, recurrent cells exhibited elevated velocity irrespective of substrate stiffness, which indicated that recurrent cells may possess inherent differential mechanosignalling ability which was reflected by higher expression of ECM proteins like Collagen IVA, MMP2 and MMP9. Moreover, mice brain injected with recurrent cells grown on 0.5kPa substrate showed higher Young’s modulus values suggesting that recurrent cells conditioned on 0.5kPa make the surrounding ECM stiffer. Importantly, inhibition of EGFR signaling, that is amplified with tissue stiffening in GBM resulted in decreased invasion, migration and proliferation in 0.5kPa recurrent cells, but interestingly survival remained unaffected, highlighting the importance of mimicking the physiological stiffness of the brain mimicking clinical scenario. Total RNA seq analysis of parent and recurrent cells grown on plastic and 0.5kPa substrate identified PLEKHA7 as significantly upregulated gene specifically in 0.5kPa recurrent sample. Higher protein expression of PLEKHA7 in recurrent GBM as compared to primary GBM was validated in patient biopsies. Accordingly, PLEKHA7 knockdown reduced invasion and survival of recurrent GBM cells. Together, these data provides a model system that captures the differential mechanosensing signals of primary and recurrent GBM cells and identifies a novel potential target specific for recurrent GBM.
Project description:Alterations in the structure and composition of Bruch's membrane (BrM) and loss of retinal pigment epithelial (RPE) cells are associated with various ocular diseases, notably age-related macular degeneration (AMD) as well as several inherited retinal diseases (IRDs). We explored the influence of stiffness as a major BrM characteristic on the RPE transcriptome and morphology. ARPE-19 cells were plated on soft ( E=30kPa ) or stiff ( E=80kPa ) polyacrylamide gels (PA gels) or standard tissue culture plastic (TCP). Next-generation sequencing (NGS) data on differentially expressed small RNAs (sRNAs) and messenger RNAs (mRNAs) were validated by qPCR, immunofluorescence or western blotting. The microRNA (miRNA) fraction of sRNAs grew with substrate stiffness and distinct miRNAs such as miR-204 or miR-222 were differentially expressed. mRNA targets of differentially expressed miRNAs were stably expressed, suggesting a homeostatic effect of miRNAs. mRNA transcription patterns were substrate stiffness-dependent, including components of Wnt/beta-catenin signaling, Microphthalmia-Associated Transcription Factor (MITF) and Dicer. These findings highlight the relevance of mechanical properties of the extracellular matrix (ECM) in cell culture experiments, especially those focusing on ECM-related diseases, such as AMD.
Project description:The substrate stiffness plays an important role in mediating the cellular behavior. Neutrophils predominate the early inflammatory response and initiate the regeneration. The neutrophil activation can be regulated by physical cues. However, it is not known how neutrophils respond to substrate stiffness, which is of significant importance in determining the outcomes of engineered tissue mimics. Herein, a three-dimensional culture system made of hydrogel for bone marrow-derived neutrophils was developed to explore the effects of varying stiffness (1.5, 2.6, and 5.7 kPa) on neutrophil phenotype and polarization states.
Project description:Purpose: Identify the effect of substrate stiffness on gene expression Methods:Evaluating for differentially expressed mRNAs in the SKOV-3 cells grown on the different substrates via High-throughput sequence Results: We found that the general direction of changes in gene expression of cells grown on the different substrates and the most significant signalling pathways and the expression of gene orthologs broadly involved in platinum drug resistance, apoptosis, cell cycle. Conclusions: Our study represents the first detailed analysis of the effects of substrate stiffness on gene expression of ovarian cancer cells.
Project description:Elevated intraocular pressure, a major risk factor of glaucoma, is caused by the abnormal function of trabecular outflow pathways. Human trabecular meshwork (HTM) tissue plays an important role in the outflow pathways. However, the molecular mechanisms that how TM cells respond to the elevated IOP are largely unknown. We cultured primary HTM cells on polyacrylamide gels with tunable stiffness corresponding to Young's moduli ranging from 1.1 to 50 kPa. Then next‐generation RNA sequencing (RNA‐seq) was performed to obtain the transcriptomic profiles of HTM cells. Bioinformatics analysis revealed that genes related to glaucoma including DCN, SPARC, and CTGF, were significantly increased with elevated substrate stiffness, as well as the global alteration of HTM transcriptome. Extracellular matrix (ECM)‐related genes were selectively activated in response to the elevated substrate stiffness, consistent with the known molecular alteration in glaucoma. Human normal and glaucomatous TM tissues were also obtained to perform RNA‐seq experiments and supported the substrate stiffness‐altered transcriptome profiles from the in vitro cell model. The current study profiled the transcriptomic changes in human TM cells upon increasing substrate stiffness. Global change of ECM‐related genes indicates that the in vitro substrate stiffness could greatly affect the biological processes of HTM cells. The in vitro HTM cell model could efficiently capture the main pathogenetic process in glaucoma patients, and provide a powerful method to investigate the underlying molecular mechanisms.