Methods in molecular biology
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For certain applications, particularly experiments involving high-resolution imaging, it is necessary to culture cells on glass slides or cover glasses. This chapter describes techniques for successfully growing human embryonic stem cells (hESCs) on glass surfaces under three different conditions - serum-containing, serum-free, and following single-cell dissociation. It is anticipated that these techniques will extrapolate to other types of pluripotent stem cells such as induced pluripotent stem cells (iPSCs) and embryonic germ cells (EGCs).
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Exon skipping is currently one of the most promising molecular therapies for Duchenne muscular -dystrophy (DMD). We have recently developed multiple exon skipping targeting exons 6 and 8 in -dystrophin mRNA of canine X-linked muscular dystrophy (CXMD), an animal model of DMD, which exhibits severe dystrophic phenotype in skeletal muscles and cardiac muscle. We have induced efficient exon skipping both in vitro and in vivo by using cocktail antisense 2'O-methyl oligonucleotides (2'OMePS) and cocktail phosphorodiamidate morpholino oligomers (morpholinos, or PMOs) and ameliorated phenotype of dystrophic dogs by systemic injections. The multiple exon skipping (double exon skipping) shown here provides the prospect of choosing deletions that optimize the functionality of the truncated dystrophin protein for DMD patients by using a common cocktail that could be validated as a single drug and also potentially applicable for more than 90% of DMD patients.
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Stem cell culture systems that rely on undefined animal-derived components introduce variability to the cultures and complicate their therapeutic use. The derivation of human embryonic stem cells and the development of methods to produce induced pluripotent stem cells combined with their potential to treat human diseases have accelerated the drive to develop xenogenic-free, chemically defined culture systems that support pluripotent self-renewal and directed differentiation. In this chapter, we describe four xeno-free culture systems that have been successful in supporting undifferentiated growth of hPSCs as well as methods for xeno-free subculture and cryopreservation of hPSCs. Each culture system consists of a xeno-free growth medium and xeno-free substratum: (1) TeSR2™ with human recombinant laminin (LN-511); (2) NutriStem™ with LN-511; (3) RegES™ with human foreskin fibroblasts (hFFs); (4) KO-SR Xeno-Free™/GF cocktail with CELLstart™ matrix.
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Breakdown of the blood-brain barrier (BBB) is present in several neurological disorders such as stroke, brain tumors, and multiple sclerosis. Noninvasive evaluation of BBB breakdown is important for monitoring disease progression and evaluating therapeutic efficacy in such disorders. One of the few techniques available for noninvasively and repeatedly localizing and quantifying BBB damage is magnetic resonance imaging (MRI). ⋯ The accuracy and reliability of two of these multiparametric MRI measures, CBF by AST and DCE-MRI determined influx of Gd-DTPA, have been established by nearly congruent quantitative autoradiographic (QAR) studies with appropriate radiotracers. In addition, some of their linkages to local pathology have been shown via corresponding light microscopy and fluorescence imaging. This chapter describes: (1) multiparametric MRI techniques with emphasis on DCE-MRI and AST-MRI; (2) the measurement of the blood-to-brain influx rate constant and CBF; and (3) the role of each in determining BBB permeability.
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Lysine acetylation of histones is one of the major epigenetic regulators of chromatin conformation and gene expression. The dynamic nature of histone acetylation is determined by the counterbalancing activity of histone acetyltransferase and histone deacetylase (HDAC) enzymes. Acetylation of histones is generally associated with open and transcriptionally active chromatin, whereas the activity of HDACs leads to histone deacetylation, condensation of chromatin, and inhibition of transcription. ⋯ Abnormal activity of HDACs has been implicated in tumorigenesis and therefore considerable effort has been put into the development of HDAC inhibitors as a means of modifying histone acetylation status and reexpressing aberrantly silenced tumor suppressor genes. This has led to the generation of a number of structurally diverse compounds that can effectively inhibit HDAC activity, thus altering chromatin structure in cancer cells. This unit discusses the methods and recent technological developments with respect to the studies of HDAC inhibition in cancer.