Project description:NG2/CSPG4 is expressed in soft tissue sarcomas, however, its function in this tumor type, and its capacity to serve as a therapeutic target are unknown. Here, we used genetically engineered mice and cells from human tumors to determine the function of Ng2/Cspg4 in soft tissue sarcoma initiation and growth. We also investigated the potential for NG2/CSPG4 mAb immunotherapy to target human sarcomas established as xenografts in mice. Inhibiting Ng2/Cspg4 expression in established soft tissue sarcomas is associated with a smaller tumor volume and a reduction in cell proliferation. Intriguingly, deleting Ng2/Cspg4 at the time of tumor initiation has the opposite effect. Gene profiling found that Igfbp3/5 are substantially downregulated when Ng2/Cspg4 is depleted at the time of tumor initiation, but upregulated or only minimally downregulated when Ng2/Cspg4 is depleted after tumor initiation. Furthermore, the normal regulation of Igfbp is blunted when Ng2/Cspg4 is deleted at the time of tumor initiation. Our data show a difference in NG2/CSPG4 function in tumor initiation and maintenance, and provides pre-clinical evidence supporting NG2/CSPG4 as a therapeutic approach in soft tissue sarcoma.
Project description:B-cell acute lymphoblastic leukemia (B-ALL) is the most common pediatric cancer, with long-term overall survival rates of 80%. However, B-ALL harboring rearrangements of the MLL gene (also known as KTM2A), hereinafter termed MLLr B-ALL, is frequently seen in infants and is associated with poor 5-year survival (<30%), frequent relapses, and refractoriness to glucocorticoids (GC). GC are an essential part of the treatment backbone for B-ALL and GC resistance is a major clinical predictor of poor outcome. Unraveling the mechanisms of GC resistance in MLLr B-ALL is, therefore, crucial to guide therapeutic strategies that deepen response after induction therapy. Neuron-glial antigen-2 (NG2) expression is a hallmark of MLLr B-ALL and is minimally expressed in healthy hematopoietic cells. We recently reported that NG2 expression is associated with poor prognosis and that anti-NG2 immunotherapy strongly reduces/delays relapse in xenograft models of MLLr B-ALL. However, despite its contribution to MLLr B-ALL pathogenesis and its diagnostic utility, the role of NG2 in MLLr-mediated leukemogenesis/chemoresistance remains elusive. We show here that NG2 is an epigenetically regulated direct target gene of the leukemic MLL-AF4 fusion protein. NG2 negatively regulates the expression of the GC receptor NR3C1, conferring GC chemoresistance to MLLr B-ALL cells in vitro and in vivo. Mechanistically, NG2 interacts with FLT3 to render ligand-independent activation of FLT3 signaling (a hallmark of MLLr B-ALL) and downregulation of NR3C1 via AP-1-mediated transrepression. Collectively, our study elucidates the role of NG2 in GC resistance in MLLr B-ALL through a FLT3/AP-1-mediated downregulation of NR3C1, providing novel therapeutic avenues for MLLr B-ALL.
Project description:Changes in the mechanical homeostasis of the temporomandibular joint (TMJ) can lead to the initiation and progression of degenerative arthropathies such as osteoarthritis (OA). Cells sense and engage with their mechanical microenvironment through interactions with the extracellular matrix. In the mandibular condylar cartilage, the pericellular microenvironment is composed of type VI collagen. NG2/CSPG4 is a transmembrane proteoglycan that binds with type VI collagen, and has been implicated in the cell stress response. The objective of this study is to define the role of NG2/CSPG4 in the cell stress response during serum starvation. To evaluate the role of the NG2/CSPG4, primary mandibular fibrochondrocytes from c57 BL/6 J and NG2/CSPG4 knockout mice (mixed sex) were cultured in normal and serum starvation conditions. To evaluate the role of the NG2/CSPG4 ectodomain, primary mandibular fibrochondrocytes were immortalized using hTERT. CRSIPR/Cas9 was used to truncate the NG2/CSPG4 ectodomain by targeting the type VI collagen binding region. Normal culture conditions were AMEM growth media supplemented with 10% FBS, penicillin, L-Glut, and plasmocin. Serum starvation conditions were Optimem media with no FBS, supplemented with penicillin, L-Glut, and plasmocin. Serum starvation was induced for 24 hours. RNA from the cells was isolated using the RNeasy kit (Qiagen). poly(A) RNA was fragmented using divalent cation buffer in elevated temperature. The DNA library construction is shown in the following workflow. Quality control analysis and quantification of the sequencing library were performed using Agilent Technologies 2100 Bioanalyzer High Sensitivity DNA Chip. Paired-ended sequencing was performed on Illumina’s NovaSeq 6000 sequencing system. Sequencing was done by LC Sciences. These data illustrate that in serum starvation conditions, NG2/CSPG4 knockout mandibular fibrochondrocytes and targeted truncation of the NG2/CSPG4 ectodomain alters the transcriptional profile of the cell, promoting biological processes associated with cell stress, migration, and ossiciation.
Project description:Changes in the mechanical homeostasis of the temporomandibular joint (TMJ) can lead to the initiation and progression of degenerative arthropathies such as osteoarthritis (OA). Cells sense and engage with their mechanical microenvironment through interactions with the extracellular matrix. In the mandibular condylar cartilage, the pericellular microenvironment is composed of type VI collagen. NG2/CSPG4 is a transmembrane proteoglycan that binds with type VI collagen, and has been implicated in the cell stress response. The objective of this study is to define the role of NG2/CSPG4 in the cell stress response during serum starvation. To evaluate the role of the NG2/CSPG4, primary mandibular fibrochondrocytes from c57 BL/6 J and NG2/CSPG4 knockout mice (mixed sex) were cultured in normal and serum starvation conditions. To evaluate the role of the NG2/CSPG4 ectodomain, primary mandibular fibrochondrocytes were immortalized using hTERT. CRSIPR/Cas9 was used to truncate the NG2/CSPG4 ectodomain by targeting the type VI collagen binding region. Normal culture conditions were AMEM growth media supplemented with 10% FBS, penicillin, L-Glut, and plasmocin. Serum starvation conditions were Optimem media with no FBS, supplemented with penicillin, L-Glut, and plasmocin. Serum starvation was induced for 24 hours. RNA from the cells was isolated using the RNeasy kit (Qiagen). poly(A) RNA was fragmented using divalent cation buffer in elevated temperature. The DNA library construction is shown in the following workflow. Quality control analysis and quantification of the sequencing library were performed using Agilent Technologies 2100 Bioanalyzer High Sensitivity DNA Chip. Paired-ended sequencing was performed on Illumina’s NovaSeq 6000 sequencing system. Sequencing was done by LC Sciences. These data illustrate that in serum starvation conditions, NG2/CSPG4 knockout mandibular fibrochondrocytes and targeted truncation of the NG2/CSPG4 ectodomain alters the transcriptional profile of the cell, promoting biological processes associated with cell stress, migration, and ossiciation.
Project description:Changes in the mechanical homeostasis of the temporomandibular joint (TMJ) can lead to the initiation and progression of degenerative arthropathies such as osteoarthritis (OA). Cells sense and engage with their mechanical microenvironment through interactions with the extracellular matrix. In the mandibular condylar cartilage, the pericellular microenvironment is composed of type VI collagen. NG2/CSPG4 is a transmembrane proteoglycan that binds with type VI collagen, and has been implicated in the cell stress response through mechanical loading-sensitive signaling networks including ERK 1/2. The objective of this study is to define the role of NG2/CSPG4 in the initiation and progression of TMJ OA and to determine if NG2/CSPG4 engages ERK 1/2 in a mechanical loading dependent manner. In vivo, we induced TMJ OA in control and NG2/CSPG4 knockout mice using a surgical destabilization approach. In control mice, NG2/CSPG4 is depleted during the early stages of TMJ OA and NG2/CSPG4 knockout mice have more severe cartilage degeneration, elevated expression of key OA proteases, and suppression of OA matrix synthesis genes. In vitro, we characterized the transcriptome and protein from control and NG2/CSPG4 knockout cells and found significant dysregulation of the ERK 1/2 signaling axis. To characterize the mechanobiological response of NG2/CSPG4, we applied mechanical loads on cell-agarose-collagen scaffolds using a compression bioreactor and illustrate that NG2/CSPG4 knockout cells fail to mechanically activate ERK 1/2 and are associated with changes in the expression of the same key OA biomarkers measured in vivo. Together, these findings implicate NG2/CSPG4 in the mechanical homeostasis of TMJ cartilage and in the progression of degenerative arthropathies including OA.
Project description:We demonstrated that deletion of the p53 tumor suppressor gene in NG2 expressing cells resulted in the development of bone and soft tissue sarcomas that closely resemble human tumors. To determine gene expression differences between NG2 expressing pericytes lacking p53 and sarcomas that arose from deletion of p53 in NG2 expressing cells, RNA sequencing analysis was implemented.
Project description:Purpose: To investigate whether the skeletal retardation observed in NG2-cre/Pot1afl/fl mice affected hematopoiesis. Methods: Whole bone marrow cells mRNA profiles of 2-week-old wild-type (NG2-cre/Pot1awt/wt) and Pot1a knockout (NG2-cre/Pot1afl/fl) mice were generated by deep sequencing, using Illumina NextSeq 500. Results: We compared the relative sizes of these subpopulations between the NG2-cre/Pot1afl/fl and control mice and found a significant reduction in cells of the B-cell lineage in NG2-cre/Pot1afl/fl marrow. Cell subpopulations associated with B-cell differentiation from hematopoietic stem/progenitor cells (HSPCs) were identified according to the expression of established marker genes. Conclusions: Bone marrow microenvironments composed of POT1a-deleted MSPCs impair B-cell development.
Project description:NG2 glia, also known as oligodendrocyte precursor cells (OPCs), play an important role in proliferation and give rise to myelinating oligodendrocytes during early brain development. In contrast to other glial cell types, the most intriguing aspect of NG2 glia is their ability to directly sense synaptic inputs from neurons. However, whether this synaptic interaction is bidirectional or unidirectional, or its physiological relevance has not yet been clarified. Here, we report that NG2 glia form synaptic complexes with hippocampal interneurons and that selective photostimulation of NG2 glia (expressing channelrhodopsin-2) functionally drives GABA release and enhances inhibitory synaptic transmission onto proximal interneurons in a microcircuit. The mechanism involves GAD67 biosynthesis and VAMP-2 containing vesicular exocytosis. Further, behavioral assays demonstrate that NG2 glia photoactivation triggers an anxiety-like behavior in vivo and induces anxiety-like behavior in a mouse model of chronic social defeat stress.