搜索结果: 'methocult media formulations for mouse hematopoietic cells serum containing'

AbstractBack to TopbackslashnNeurons produced from stem cells have emerged as a tool to identify new therapeutic targets for neurological diseases such as amyotrophic lateral sclerosis (ALS). However,it remains unclear to what extent these new mechanistic insights will translate to animal models,an important step in the validation of new targets. Previously,we found that glia from mice carrying the SOD1G93A mutation,a model of ALS,were toxic to stem cell–derived human motor neurons. We use pharmacological and genetic approaches to demonstrate that the prostanoid receptor DP1 mediates this glial toxicity. Furthermore,we validate the importance of this mechanism for neural degeneration in vivo. Genetic ablation of DP1 in SOD1G93A mice extended life span,decreased microglial activation,and reduced motor neuron loss. Our findings suggest that blocking DP1 may be a therapeutic strategy in ALS and demonstrate that discoveries from stem cell models of disease can be corroborated in vivo. View Publication

The low success rate of animal cloning by somatic cell nuclear transfer (SCNT) is believed to be associated with epigenetic errors including abnormal DNA hypermethylation. Recently,we elucidated by using round spermatids that,after nuclear transfer,treatment of zygotes with trichostatin A (TSA),an inhibitor of histone deacetylase,can remarkably reduce abnormal DNA hypermethylation depending on the origins of transferred nuclei and their genomic regions [S. Kishigami,N. Van Thuan,T. Hikichi,H. Ohta,S. Wakayama. E. Mizutani,T. Wakayama,Epigenetic abnormalities of the mouse paternal zygotic genome associated with microinsemination of round spermatids,Dev. Biol. (2005) in press]. Here,we found that 5-50 nM TSA-treatment for 10 h following oocyte activation resulted in more efficient in vitro development of somatic cloned embryos to the blastocyst stage from 2- to 5-fold depending on the donor cells including tail tip cells,spleen cells,neural stem cells,and cumulus cells. This TSA-treatment also led to more than 5-fold increase in success rate of mouse cloning from cumulus cells without obvious abnormality but failed to improve ES cloning success. Further,we succeeded in establishment of nuclear transfer-embryonic stem (NT-ES) cells from TSA-treated cloned blastocyst at a rate three times higher than those from untreated cloned blastocysts. Thus,our data indicate that TSA-treatment after SCNT in mice can dramatically improve the practical application of current cloning techniques. View Publication

Leptin is detected in the sera,and leptin receptors are expressed in the cerebrum of mouse embryos,suggesting that leptin plays a role in cerebral development. Compared with the wild type,leptin-deficient (ob/ob) mice had fewer cells at embryonic day (E) 16 and E18 and had fewer 5-bromo-2'-deoxyuridine(+) cells at E14 and E16 in the neuroepithelium. Intracerebroventricular leptin injection in E14 ob/ob embryos increased the number of neuroepithelium cells at E16. In cultured neurosphere cells,leptin treatment increased Hes1 mRNA expression and maintained neural progenitors. Astrocyte differentiation was induced by low-dose (0.1 microg/ml) but not high-dose (1 microg/ml) leptin. High-dose leptin decreased Id mRNA and increased Ngn1 mRNA in neurosphere cells. The neuropeptide Y mRNA level in the cortical plate was lower in ob/ob than the wild type at E16 and E18. These results suggest that leptin maintains neural progenitors and is related to glial and neuronal development in embryos. View Publication

Within high-grade gliomas,the precise identities and functional roles of stem-like cells remain unclear. In the normal neurogenic niche,ID (Inhibitor of DNA-binding) genes maintain self-renewal and multipotency of adult neural stem cells. Using PDGF- and KRAS-driven murine models of gliomagenesis,we show that high Id1 expression (Id1(high)) identifies tumor cells with high self-renewal capacity,while low Id1 expression (Id1(low)) identifies tumor cells with proliferative potential but limited self-renewal capacity. Surprisingly,Id1(low) cells generate tumors more rapidly and with higher penetrance than Id1(high) cells. Further,eliminating tumor cell self-renewal through deletion of Id1 has modest effects on animal survival,while knockdown of Olig2 within Id1(low) cells has a significant survival benefit,underscoring the importance of non-self-renewing lineages in disease progression. View Publication

Williams syndrome is a genetic neurodevelopmental disorder characterized by an uncommon hypersociability and a mosaic of retained and compromised linguistic and cognitive abilities. Nearly all clinically diagnosed individuals with Williams syndrome lack precisely the same set of genes,with breakpoints in chromosome band 7q11.23 (refs 1-5). The contribution of specific genes to the neuroanatomical and functional alterations,leading to behavioural pathologies in humans,remains largely unexplored. Here we investigate neural progenitor cells and cortical neurons derived from Williams syndrome and typically developing induced pluripotent stem cells. Neural progenitor cells in Williams syndrome have an increased doubling time and apoptosis compared with typically developing neural progenitor cells. Using an individual with atypical Williams syndrome,we narrowed this cellular phenotype to a single gene candidate,frizzled 9 (FZD9). At the neuronal stage,layer V/VI cortical neurons derived from Williams syndrome were characterized by longer total dendrites,increased numbers of spines and synapses,aberrant calcium oscillation and altered network connectivity. Morphometric alterations observed in neurons from Williams syndrome were validated after Golgi staining of post-mortem layer V/VI cortical neurons. This model of human induced pluripotent stem cells fills the current knowledge gap in the cellular biology of Williams syndrome and could lead to further insights into the molecular mechanism underlying the disorder and the human social brain. View Publication

A network of transcription factors (TFs) determines cell identity,but identity can be altered by overexpressing a combination of TFs. However,choosing and verifying combinations of TFs for specific cell differentiation have been daunting due to the large number of possible combinations of 2,000 TFs. Here,we report the identification of individual TFs for lineage-specific cell differentiation based on the correlation matrix of global gene expression profiles. The overexpression of identified TFs-Myod1,Mef2c,Esx1,Foxa1,Hnf4a,Gata2,Gata3,Myc,Elf5,Irf2,Elf1,Sfpi1,Ets1,Smad7,Nr2f1,Sox11,Dmrt1,Sox9,Foxg1,Sox2,or Ascl1-can direct efficient,specific,and rapid differentiation into myocytes,hepatocytes,blood cells,and neurons. Furthermore,transfection of synthetic mRNAs of TFs generates their appropriate target cells. These results demonstrate both the utility of this approach to identify potent TFs for cell differentiation,and the unanticipated capacity of single TFs directly guides differentiation to specific lineage fates. View Publication

Mechanisms that maintain cancer stem cells are crucial to tumour progression. The ID2 protein supports cancer hallmarks including the cancer stem cell state. HIFα transcription factors,most notably HIF2α (also known as EPAS1),are expressed in and required for maintenance of cancer stem cells (CSCs). However,the pathways that are engaged by ID2 or drive HIF2α accumulation in CSCs have remained unclear. Here we report that DYRK1A and DYRK1B kinases phosphorylate ID2 on threonine 27 (Thr27). Hypoxia downregulates this phosphorylation via inactivation of DYRK1A and DYRK1B. The activity of these kinases is stimulated in normoxia by the oxygen-sensing prolyl hydroxylase PHD1 (also known as EGLN2). ID2 binds to the VHL ubiquitin ligase complex,displaces VHL-associated Cullin 2,and impairs HIF2α ubiquitylation and degradation. Phosphorylation of Thr27 of ID2 by DYRK1 blocks ID2-VHL interaction and preserves HIF2α ubiquitylation. In glioblastoma,ID2 positively modulates HIF2α activity. Conversely,elevated expression of DYRK1 phosphorylates Thr27 of ID2,leading to HIF2α destabilization,loss of glioma stemness,inhibition of tumour growth,and a more favourable outcome for patients with glioblastoma. View Publication

AIM Bevacizumab has been reported to result in increased tumor invasion when used to treat malignant glioma. We hypothesized that BMP4 would prevent diffuse tumor infiltration induced by bevacizumab for malignant glioma in a xenograft model. METHODS Human glioblastoma (GBM) tumor cells were implanted in the striatum of immunocompromised mice. The animals were treated with bevacizumab and BMP4. Tumor growth and invasion were measured. RESULTS The bevacizumab-treated mice had increased survival compared with control animals (p = 0.02). BMP4 alone did not result in improved survival (p = 1.0). The bevacizumab (p = 0.006) and bevacizumab plus BMP4 (p = 0.006) groups demonstrated significantly decreased total tumor size compared with control. Tumor invasion was significantly decreased in the bevacizumab (p = 0.005),BMP4 (p = 0.04) alone and bevacizumab plus BMP4 (p = 0.002) groups compared with control. No synergistic effect between bevacizumab and BMP4 was observed. CONCLUSION Bevacizumab treatment did not result in diffuse infiltration of human GBM in a mouse xenograft model. BMP4 did have an independent favorable effect on GBM that was not synergistic with bevacizumab treatment. View Publication