scholarly journals TMOD-04. CHARACTERIZATION OF MUTANT IDH1 OLIGODENDROGLIOMAS

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi263-vi263
Author(s):  
Rick Heinz ◽  
Sheri Holmen
Keyword(s):  
Molecular Mechanisms ◽  
Gene Knockout ◽  
Genomic Analysis ◽  
World Health ◽  
Low Grade ◽  
Idh Mutation ◽  
Loss Of Function ◽  
In Vivo Models ◽  
Mutant Idh1

Abstract Gliomas are the most common primary central nervous system malignancy in adults, but the molecular mechanisms responsible for their development and progression are not fully understood. Recent genomic analysis of World Health Organization grade II-III gliomas identifies 3 molecular subtypes of low grade glioma: no IDH mutation; IDH mutation without 1p/19q co-deletion; and IDH mutation with 1p/19q co-deletion. The latter, categorized as oligodendroglioma, commonly expresses loss of function mutations in CIC, FUBP1, and activation of PIK3CA. However, it is unknown if any of these mutations are sufficient to promote glioma development in cooperation with mutant IDH. Furthermore, research in oligodendroglioma is hampered by the lack of in vivo models of this specific glioma subtype. By utilizing the established RCAS/TVA somatic cell gene delivery method, mutant IDH1 can be expressed in the brains of mice. The tumorgenicity of other mutated genes associated with oligodendroglioma can be determined using additional methods such as conditional gene knockout and in vivo CRISPR-Cas9 mediated deletion. A mouse model for oligodendroglioma may identify new targetable genetic drivers of oligodendroglioma that will be useful for testing novel therapeutic strategies.

scholarly journals An in vivo model allowing continuous observation of human vascular formation in the same animal over time

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yohei Tsukada ◽  
Fumitaka Muramatsu ◽  
Yumiko Hayashi ◽  
Chiaki Inagaki ◽  
Hang Su ◽  
...  
Keyword(s):  
Blood Vessel ◽  
Blood Vessels ◽  
Human Blood ◽  
Molecular Mechanisms ◽  
Human Tumor ◽  
Continuous Observation ◽  
In Vivo Models ◽  
Cranial Window ◽  
Pathological Conditions

AbstractAngiogenesis contributes to numerous pathological conditions. Understanding the molecular mechanisms of angiogenesis will offer new therapeutic opportunities. Several experimental in vivo models that better represent the pathological conditions have been generated for this purpose in mice, but it is difficult to translate results from mouse to human blood vessels. To understand human vascular biology and translate findings into human research, we need human blood vessel models to replicate human vascular physiology. Here, we show that human tumor tissue transplantation into a cranial window enables engraftment of human blood vessels in mice. An in vivo imaging technique using two-photon microscopy allows continuous observation of human blood vessels until at least 49 days after tumor transplantation. These human blood vessels make connections with mouse blood vessels as shown by the finding that lectin injected into the mouse tail vein reaches the human blood vessels. Finally, this model revealed that formation and/or maintenance of human blood vessels depends on VEGFR2 signaling. This approach represents a useful tool to study molecular mechanisms of human blood vessel formation and to test effects of drugs that target human blood vessels in vivo to show proof of concept in a preclinical model.

scholarly journals Classification of lymphoid neoplasms: the microscope as a tool for disease discovery

Blood ◽  
2008 ◽  
Vol 112 (12) ◽  
pp. 4384-4399 ◽  
Author(s):  
Elaine S. Jaffe ◽  
Nancy Lee Harris ◽  
Harald Stein ◽  
Peter G. Isaacson
Keyword(s):  
Molecular Mechanisms ◽  
Nk Cell ◽  
Clinical Manifestations ◽  
Lymphoid Cells ◽  
World Health ◽  
International Studies ◽  
Lymphocyte Function ◽  
Lymphoid Neoplasms

AbstractIn the past 50 years, we have witnessed explosive growth in the understanding of normal and neoplastic lymphoid cells. B-cell, T-cell, and natural killer (NK)–cell neoplasms in many respects recapitulate normal stages of lymphoid cell differentiation and function, so that they can be to some extent classified according to the corresponding normal stage. Likewise, the molecular mechanisms involved the pathogenesis of lymphomas and lymphoid leukemias are often based on the physiology of the lymphoid cells, capitalizing on deregulated normal physiology by harnessing the promoters of genes essential for lymphocyte function. The clinical manifestations of lymphomas likewise reflect the normal function of lymphoid cells in vivo. The multiparameter approach to classification adopted by the World Health Organization (WHO) classification has been validated in international studies as being highly reproducible, and enhancing the interpretation of clinical and translational studies. In addition, accurate and precise classification of disease entities facilitates the discovery of the molecular basis of lymphoid neoplasms in the basic science laboratory.

scholarly journals Assessment of phagocytic activity in live macrophages-tumor cells co-cultures by Confocal and Nomarski Microscopy

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Dalia Martinez-Marin ◽  
Courtney Jarvis ◽  
Thomas Nelius ◽  
Stéphanie Filleur
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Cells ◽  
Phagocytic Activity ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Functional Assay ◽  
Loss Of Function ◽  
Multiple Cancer

Abstract Macrophages have been recognized as the main inflammatory component of the tumor microenvironment. Although often considered as beneficial for tumor growth and disease progression, tumor-associated macrophages have also been shown to be detrimental to the tumor depending on the tumor microenvironment. Therefore, understanding the molecular interactions between macrophages and tumor cells in relation to macrophages functional activities such as phagocytosis is critical for a better comprehension of their tumor-modulating action. Still, the characterization of these molecular mechanisms in vivo remains complicated due to the extraordinary complexity of the tumor microenvironment and the broad range of tumor-associated macrophage functions. Thus, there is an increasing demand for in vitro methodologies to study the role of cell–cell interactions in the tumor microenvironment. In the present study, we have developed live co-cultures of macrophages and human prostate tumor cells to assess the phagocytic activity of macrophages using a combination of Confocal and Nomarski Microscopy. Using this model, we have emphasized that this is a sensitive, measurable, and highly reproducible functional assay. We have also highlighted that this assay can be applied to multiple cancer cell types and used as a selection tool for a variety of different types of phagocytosis agonists. Finally, combining with other studies such as gain/loss of function or signaling studies remains possible. A better understanding of the interactions between tumor cells and macrophages may lead to the identification of new therapeutic targets against cancer.

scholarly journals Biophysical studies of protein misfolding and aggregation in in vivo models of Alzheimer's and Parkinson's diseases

2020 ◽  
Vol 53 ◽  
Author(s):  
Tessa Sinnige ◽  
Karen Stroobants ◽  
Christopher M. Dobson ◽  
Michele Vendruscolo
Keyword(s):  
Protein Misfolding ◽  
Molecular Mechanisms ◽  
Amyloid Β ◽  
Therapeutic Interventions ◽  
In Vivo Models ◽  
Disease Modifying Drugs ◽  
Parkinson’S Diseases ◽  
Protein Misfolding And Aggregation

Abstract Neurodegenerative disorders, including Alzheimer's (AD) and Parkinson's diseases (PD), are characterised by the formation of aberrant assemblies of misfolded proteins. The discovery of disease-modifying drugs for these disorders is challenging, in part because we still have a limited understanding of their molecular origins. In this review, we discuss how biophysical approaches can help explain the formation of the aberrant conformational states of proteins whose neurotoxic effects underlie these diseases. We discuss in particular models based on the transgenic expression of amyloid-β (Aβ) and tau in AD, and α-synuclein in PD. Because biophysical methods have enabled an accurate quantification and a detailed understanding of the molecular mechanisms underlying protein misfolding and aggregation in vitro, we expect that the further development of these methods to probe directly the corresponding mechanisms in vivo will open effective routes for diagnostic and therapeutic interventions.

Mesenchymal folliculin is required for alveolar development: implications for cystic lung disease in Birt-Hogg-Dubé syndrome

Thorax ◽  
2020 ◽  
Vol 75 (6) ◽  
pp. 486-493 ◽  
Author(s):  
Ling Chu ◽  
Yongfeng Luo ◽  
Hui Chen ◽  
Qing Miao ◽  
Larry Wang ◽  
...  
Keyword(s):  
Lung Disease ◽  
Molecular Mechanisms ◽  
Statistical Significance ◽  
Mesenchymal Progenitor Cells ◽  
Loss Of Function ◽  
Cystic Lung ◽  
Alveolar Development ◽  
Cystic Lung Disease ◽  
Pulmonary Cysts

BackgroundPulmonary cysts and spontaneous pneumothorax are presented in most patients with Birt-Hogg-Dubé (BHD) syndrome, which is caused by loss of function mutations in the folliculin (FLCN) gene. The pathogenic mechanisms underlying the cystic lung disease in BHD are poorly understood.MethodsMesenchymal Flcn was specifically deleted in mice or in cultured lung mesenchymal progenitor cells using a Cre/loxP approach. Dynamic changes in lung structure, cellular and molecular phenotypes and signalling were measured by histology, immunofluorescence staining and immunoblotting.ResultsDeletion of Flcn in mesoderm-derived mesenchymal cells results in significant reduction of postnatal alveolar growth and subsequent alveolar destruction, leading to cystic lesions. Cell proliferation and alveolar myofibroblast differentiation are inhibited in the Flcn knockout lungs, and expression of the extracellular matrix proteins Col3a1 and elastin are downregulated. Signalling pathways including mTORC1, AMP-activated protein kinase, ERK1/2 and Wnt-β-catenin are differentially affected at different developmental stages. All the above changes have statistical significance (p<0.05).ConclusionsMesenchymal Flcn is an essential regulator during alveolar development and maintenance, through multiple cellular and molecular mechanisms. The mesenchymal Flcn knockout mouse model provides the first in vivo disease model that may recapitulate the stages of cyst development in human BHD. These findings elucidate the developmental origins and mechanisms of lung disease in BHD.

Molecular mechanisms driving the in vivo development of OXA-10-mediated resistance to ceftolozane/tazobactam and ceftazidime/avibactam during treatment of XDR Pseudomonas aeruginosa infections

2020 ◽  
Vol 76 (1) ◽  
pp. 91-100
Author(s):  
Jorge Arca-Suárez ◽  
Cristina Lasarte-Monterrubio ◽  
Bruno-Kotska Rodiño-Janeiro ◽  
Gabriel Cabot ◽  
Juan Carlos Vázquez-Ucha ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Molecular Mechanisms ◽  
Genomic Analysis ◽  
Resistance Mechanisms ◽  
Comparative Genomic ◽  
Development Of Resistance ◽  
Structural Impact ◽  
Genetic Context

Abstract Background The development of resistance to ceftolozane/tazobactam and ceftazidime/avibactam during treatment of Pseudomonas aeruginosa infections is concerning. Objectives Characterization of the mechanisms leading to the development of OXA-10-mediated resistance to ceftolozane/tazobactam and ceftazidime/avibactam during treatment of XDR P. aeruginosa infections. Methods Four paired ceftolozane/tazobactam- and ceftazidime/avibactam-susceptible/resistant isolates were evaluated. MICs were determined by broth microdilution. STs, resistance mechanisms and genetic context of β-lactamases were determined by genotypic methods, including WGS. The OXA-10 variants were cloned in PAO1 to assess their impact on resistance. Models for the OXA-10 derivatives were constructed to evaluate the structural impact of the amino acid changes. Results The same XDR ST253 P. aeruginosa clone was detected in all four cases evaluated. All initial isolates showed OprD deficiency, produced an OXA-10 enzyme and were susceptible to ceftazidime, ceftolozane/tazobactam, ceftazidime/avibactam and colistin. During treatment, the isolates developed resistance to all cephalosporins. Comparative genomic analysis revealed that the evolved resistant isolates had acquired mutations in the OXA-10 enzyme: OXA-14 (Gly157Asp), OXA-794 (Trp154Cys), OXA-795 (ΔPhe153-Trp154) and OXA-824 (Asn143Lys). PAO1 transformants producing the evolved OXA-10 derivatives showed enhanced ceftolozane/tazobactam and ceftazidime/avibactam resistance but decreased meropenem MICs in a PAO1 background. Imipenem/relebactam retained activity against all strains. Homology models revealed important changes in regions adjacent to the active site of the OXA-10 enzyme. The blaOXA-10 gene was plasmid borne and acquired due to transposition of Tn6746 in the pHUPM plasmid scaffold. Conclusions Modification of OXA-10 is a mechanism involved in the in vivo acquisition of resistance to cephalosporin/β-lactamase inhibitor combinations in P. aeruginosa.

scholarly journals IMMU-28. DEFINING MOLECULAR MECHANISMS OF RESISTANCE TO GLIOBLASTOMA (GBM) IMMUNITY USING A NOVEL CRISPR/CAS9 IN VIVO LOSS-OF-FUNCTION SCREENING PLATFORM

2017 ◽  
Vol 19 (suppl_6) ◽  
pp. vi118-vi118
Author(s):  
Martha R Neagu ◽  
Maria Carmela Speranza ◽  
Robert T Manguso ◽  
Sean E Lawler ◽  
Gordon J Freeman ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Loss Of Function ◽  
Mechanisms Of Resistance ◽  
Screening Platform

scholarly journals Clonal expansion and epigenetic reprogramming following deletion or amplification of mutant IDH1

2017 ◽  
Vol 114 (40) ◽  
pp. 10743-10748 ◽  
Author(s):  
Tali Mazor ◽  
Charles Chesnelong ◽  
Aleksandr Pankov ◽  
Llewellyn E. Jalbert ◽  
Chibo Hong ◽  
...  
Keyword(s):  
Copy Number ◽  
Cpg Island ◽  
Clonal Expansion ◽  
Low Grade ◽  
Copy Number Alterations ◽  
Wild Type ◽  
Mutant Idh1

IDH1 mutation is the earliest genetic alteration in low-grade gliomas (LGGs), but its role in tumor recurrence is unclear. Mutant IDH1 drives overproduction of the oncometabolite d-2-hydroxyglutarate (2HG) and a CpG island (CGI) hypermethylation phenotype (G-CIMP). To investigate the role of mutant IDH1 at recurrence, we performed a longitudinal analysis of 50 IDH1 mutant LGGs. We discovered six cases with copy number alterations (CNAs) at the IDH1 locus at recurrence. Deletion or amplification of IDH1 was followed by clonal expansion and recurrence at a higher grade. Successful cultures derived from IDH1 mutant, but not IDH1 wild type, gliomas systematically deleted IDH1 in vitro and in vivo, further suggestive of selection against the heterozygous mutant state as tumors progress. Tumors and cultures with IDH1 CNA had decreased 2HG, maintenance of G-CIMP, and DNA methylation reprogramming outside CGI. Thus, while IDH1 mutation initiates gliomagenesis, in some patients mutant IDH1 and 2HG are not required for later clonal expansions.

scholarly journals Genetically Altered Mouse Models: the Good, the Bad, and the Ugly

2003 ◽  
Vol 14 (3) ◽  
pp. 154-174 ◽  
Author(s):  
Tamizchelvi Thyagarajan ◽  
Satish Totey ◽  
Mary Jo S. Danton ◽  
Ashok B. Kulkarni
Keyword(s):  
Gene Targeting ◽  
Mouse Models ◽  
Molecular Mechanisms ◽  
Gene Knockout ◽  
Genetically Engineered ◽  
Murine Models ◽  
Functional Roles ◽  
Targeted Gene Disruption ◽  
Gene Knockout Mouse

Targeted gene disruption in mice is a powerful tool for generating murine models for human development and disease. While the human genome program has helped to generate numerous candidate genes, few genes have been characterized for their precise in vivo functions. Gene targeting has had an enormous impact on our ability to delineate the functional roles of these genes. Many gene knockout mouse models faithfully mimic the phenotypes of the human diseases. Because some models display an unexpected or no phenotype, controversy has arisen about the value of gene-targeting strategies. We argue in favor of gene-targeting strategies, provided they are used with caution, particularly in interpreting phenotypes in craniofacial and oral biology, where many genes have pleiotropic roles. The potential pitfalls are outweighed by the unique opportunities for developing and testing different therapeutic strategies before they are introduced into the clinic. In the future, we believe that genetically engineered animal models will be indispensable for gaining important insights into the molecular mechanisms underlying development, as well as disease pathogenesis, diagnosis, prevention, and treatment.

scholarly journals Revealing the role of phospholipase Cβ3 in the regulation of VEGF-induced vascular permeability

Blood ◽  
2012 ◽  
Vol 120 (11) ◽  
pp. 2167-2173 ◽  
Author(s):  
Luke H. Hoeppner ◽  
Kathryn N. Phoenix ◽  
Karl J. Clark ◽  
Resham Bhattacharya ◽  
Xun Gong ◽  
...  
Keyword(s):  
Vascular Permeability ◽  
Real Time ◽  
Molecular Mechanisms ◽  
Negative Regulator ◽  
Transgenic Zebrafish ◽  
Genetic Studies ◽  
In Vivo Models ◽  
Ischemic Diseases

AbstractVEGF induces vascular permeability (VP) in ischemic diseases and cancer, leading to many pathophysiological consequences. The molecular mechanisms by which VEGF acts to induce hyperpermeability are poorly understood and in vivo models that easily facilitate real-time, genetic studies of VP do not exist. In the present study, we report a heat-inducible VEGF transgenic zebrafish (Danio rerio) model through which VP can be monitored in real time. Using this approach with morpholino-mediated gene knock-down and knockout mice, we describe a novel role of phospholipase Cβ3 as a negative regulator of VEGF-mediated VP by regulating intracellular Ca2+ release. Our results suggest an important effect of PLCβ3 on VP and provide a new model with which to identify genetic regulators of VP crucial to several disease processes.

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