Matrix stiffness-dependent regulation of immunomodulatory genes in human MSCs is associated with the lncRNA CYTOR
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ABSTRACT: Previous studies have demonstrated that the physical properties of biomaterials can be adjusted to program therapeutically relevant functions in encapsulated mesenchymal stromal cells (MSCs). However, the intracellular pathways affected by mechanical cues in this cell type are not well understood. An understanding of the pertinent factors involved would not only aid in the rational design of substrates but also uncover targetable mechanisms that can facilitate the engineering of MSCs for cell therapies. Here, a bone marrow-mimetic hydrogel is employed to systematically explore the stiffness-responsive transcriptome of MSCs. High matrix rigidity impedes integrin-collagen adhesions which yields changes in cell morphology that are characterized by a contractile network of actin proximal to the cell membrane. This results in a suppression of ECM-regulatory genes involved in the remodeling of collagen fibrils and an upregulation of secreted immunomodulatory factors. Moreover, an investigation of long non-coding RNAs reveals that CYTOR contributes to these stiffness-driven changes in gene abundance. A robust knockdown of CYTOR using antisense oligonucleotides enhances the expression of numerous mechanoresponsive cytokines and chemokines to levels exceeding what is achievable by modulating matrix stiffness alone. Taken together, these findings emphasize the utility in studying previously unexplored mechanisms of mechanotransduction to inform novel strategies for enhancing the efficacy of MSC-based therapies.
Project description:The long noncoding RNA CYTOR has been linked to poor prognosis of cancer, this includes chemo- and radioresistance. Knowing the mechanisms of CYTOR can benefit current cancer therapeuitics. To examine the mechanisms of CYTOR on K562, we performed CRISPRi to knock it down. RNA sequencing were then performed on these knocked down and wild type cells. This is followed by differential gene expression analysis to determine genes and lncRNAs that are differentially regulated when CYTOR is silenced.
Project description:Oral squamous cell carcinoma (OSCC), the most common malignancy of the oral and maxillofacial region, severely affects human health. However, current treatments for OSCC commonly show only a ~60% five-year survival rate of patients with distant metastases, indicating an urgent need for targeted treatments for patients with advanced metastases. Here, we report a survival-related long non-coding RNA, CYTOR, which is highly expressed in the lesions of oral cancer patients. We found that CYTOR can promote both migration and invasion in oral cancer cells as well as the epithelial-mesenchymal transition (EMT). RNA-sequencing of CYTOR-knockdown oral cancer cells revealed that CYTOR can regulate mitochondrial respiration and RNA splicing. Mechanistically, we found that nuclear-localized CYTOR interacts with HNRNPC, resulting in stabilization of ZEB1 mRNAs by inhibiting the nondegradative ubiquitination of HNRNPC. By synthesizing CYTOR-targeting small interfering RNAs (siRNAs) encapsulated in Nanoscale Metal Organic Frameworks (NMOFs), we demonstrate the targeted suppression of CYTOR to inhibit invasion and metastasis of oral cancer cells in a nude mouse model. Cumulatively, this study reveals the potential role of the CYTOR-HNRNPC-ZEB1 axis in regulating mitochondrial metabolism and glycolysis of oral cancer cells, and illustrates the effective use of lncRNA targeting in anti-metastatic cancer therapies.
Project description:Matrix stiffness is a central regulator of fibroblast function. However, the transcriptional mechanisms linking matrix stiffness to changes in fibroblast phenotype are incompletely understood. Here, we evaluated the effect of matrix stiffness on genome-wide chromatin accessibility in freshly-isolated lung fibroblasts using ATAC-seq. We found higher matrix stiffness profoundly increased global chromatin accessibility relative to lower matrix stiffness, and these alterations were in close genomic proximity to known pro-fibrotic gene programs. Motif analysis of these regulated genomic loci identified ZNF416 as a putative mediator of fibroblast stiffness responses. Genome occupancy analysis using ChIP-seq confirmed that ZNF416 occupies a broad range of genes implicated in fibroblast activation and tissue-fibrosis, with relatively little overlap in genomic occupancy with other mechanoresponsive and pro-fibrotic transcriptional regulators. Using loss and gain of function studies we demonstrated that ZNF416 plays a critical role in fibroblast proliferation, extracellular matrix synthesis and contractile function. Together these observations identify ZNF416 as novel mechano-activated transcriptional regulator of fibroblast biology.
Project description:Matrix stiffness is a central regulator of fibroblast function. However, the transcriptional mechanisms linking matrix stiffness to changes in fibroblast phenotype are incompletely understood. Here, we evaluated the effect of matrix stiffness on genome-wide chromatin accessibility in freshly-isolated lung fibroblasts using ATAC-seq. We found higher matrix stiffness profoundly increased global chromatin accessibility relative to lower matrix stiffness, and these alterations were in close genomic proximity to known pro-fibrotic gene programs. Motif analysis of these regulated genomic loci identified ZNF416 as a putative mediator of fibroblast stiffness responses. Genome occupancy analysis using ChIP-seq confirmed that ZNF416 occupies a broad range of genes implicated in fibroblast activation and tissue-fibrosis, with relatively little overlap in genomic occupancy with other mechanoresponsive and pro-fibrotic transcriptional regulators. Using loss and gain of function studies we demonstrated that ZNF416 plays a critical role in fibroblast proliferation, extracellular matrix synthesis and contractile function. Together these observations identify ZNF416 as novel mechano-activated transcriptional regulator of fibroblast biology.
Project description:Mesenchymal stromal/stem cells (MSCs) are a heterogeneous population of multipotent progenitors that contribute to tissue regeneration and homeostasis. MSCs assess extracellular elasticity by probing resistance to applied forces via adhesion, cytoskeletal, and nuclear mechanotransducers, that direct differentiation toward soft or stiff tissue lineages. Even under controlled conditions, MSC differentiation exhibits substantial cell-to-cell variation that remains poorly characterized. By single-cell transcriptional profiling of naïve, matrix-conditioned, and early differentiation state cells, we identified distinct MSC subpopulations with distinct mechanosensitivities, differentiation capacities, and cell cycling. We showed that soft matrices support adipogenesis of multipotent cells and endochondral ossification of non-adipogenic cells, whereas intramembranous ossification and pre-osteoblast proliferation are enhanced by stiff matrices. Using diffusion pseudotime mapping, we delineated hierarchical matrix-directed differentiation and identified mechanoresponsive genes. We found that tropomyosin-1 (TPM1) is highly sensitive to stiffness cues both at RNA and protein levels and that changes in expression of TPM1 determine adipogenic or osteogenic fates. Thus, cell-to-cell variation in tropomyosin-mediated matrix-sensing contributes to impaired differentiation with implications to the biomedical potential of MSCs.
Project description:We report that macrophage elasticity plays a dominant role in bacterial phagocytosis, release of TNF-alpha, and production of reactive oxygen species. We show that macrophage elasticity is modulated by mechanical factors including substrate rigidity and substrate stretch. Changes in macrophage elasticity are dependent upon the degree of actin polymerization, and mediated in part through small rhoGTPase activity. Moreover, the functional effects of macrophage elasticity are not predicted by gene expression profiles. Murine RAW 267.4 macrophages were separately grown on 2 matrix stiffness levels (1200, 150000 Pascals) for 0, 2, 6, 18 hours with 3 replicate sample experiments per condition. Total RNA extracted from the cells and profiled by microarrays. Keywords: Murine RAW 267.4 macrophage, matrix stiffness, phagocytosis, cell elasticity.
Project description:The transcriptional profile of MDA-MB-231 cells silenced for CYTOR (LINC00152, long intergenic non-protein coding RNA 152) was compared to LNA-control-treated MDA-MB-231 cells to identify potential CYTOR targets.
Project description:The implementation of antiretroviral therapy (ART) has effectively restricted the transmission of Human Immunodeficiency Virus (HIV) and improved overall clinical outcomes. However, a complete cure for HIV remains out of reach, as the virus persists in a stable pool of infected cell reservoir that is resistant to therapy and thus a main barrier towards complete elimination of viral infection. While the mechanisms by which host proteins govern viral gene expression and latency are well-studied, the emerging regulatory functions of non-coding RNAs (ncRNA) in the context of T cell activation, HIV gene expression and viral latency have not yet been thoroughly explored. Here, we report the identification of the Cytoskeleton Regulator (CYTOR) long non-coding RNA (lncRNA) as an activator of HIV gene expression that is upregulated following T cell stimulation. Functional studies show that CYTOR suppresses viral latency by directly binding to the HIV promoter and associating with the cellular positive transcription elongation factor (P-TEFb) to activate viral gene expression. CYTOR also plays a global role in regulating cellular gene expression, including those involved in controlling actin dynamics. Depletion of CYTOR expression reduces cytoplasmic actin polymerization in response to T cell activation. In addition, treating HIV-infected cells with pharmacological inhibitors of actin polymerization reduces HIV gene expression. We conclude that both direct and indirect effects of CYTOR regulate HIV gene expression.