Haploid pluripotent stem cells, such as haploid embryonic stem cells (haESCs), facilitate the genetic study of recessive traits. In vitro, fish haESCs maintain haploidy in both undifferentiated and differentiated states, but whether mammalian haESCs can preserve pluripotency in the haploid state has not been tested. Here, we report that mouse haESCs can differentiate in vitro into haploid epiblast stem cells (haEpiSCs), which maintain an intact haploid genome, unlimited self-renewal potential, and durable pluripotency to differentiate into various tissues in vitro and in vivo. Mechanistically, the maintenance of self-renewal potential depends on the Activin/bFGF pathway. We further show that haEpiSCs can differentiate in vitro into haploid progenitor-like cells.
Durable pluripotency and haploidy in epiblast stem cells derived from haploid embryonic stem cells in vitro.
Specimen part
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Androgenetic haploid embryonic stem cells produce live transgenic mice.
Specimen part, Cell line
View SamplesHaploid stem cells offer an easy-to-manipulate genetic system and therefore have great values for studies of recessive phenotypes. Here, we show that mouse androgenetic haploid ES (ahES) cell lines can be established by transferring sperm into enucleated oocyte. The ahES cells maintain haploidy and stable growth over 30 passages, express pluripotent markers, possess the ability to differentiate into all three germ-layers in vitro and in vivo, and contribute to germline of chimeras when injected into blastocysts. Although epigenetically distinct from sperm cells, the ahES cells can produce viable and fertile progenies after intracytoplasmic injection into mature oocytes. The oocyte injection procedure can also produce viable transgenic mice from genetically engineered ahES cells.
Androgenetic haploid embryonic stem cells produce live transgenic mice.
Specimen part, Cell line
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Protein kinase c-β-dependent activation of NF-κB in stromal cells is indispensable for the survival of chronic lymphocytic leukemia B cells in vivo.
Specimen part, Cell line
View SamplesTumor cell survival critically depends on heterotypic communication with benign cells in the microenvironment. Here we describe a novel survival signaling pathway activated in stromal cells by contact to B-cells from chronic lymphocytic leukemia (CLL) patients. The expression of PKC-II and the subsequent activation of NF-B in bone marrow stromal cells is a prerequisite to support the survival of malignant B-cells. PKC- knockout mice are insusceptible to CLL-transplantations, underscoring the in vivo significance of the PKC-II- NF-B signaling pathway in the tumor microenvironment. Upregulated stromal PKC-II in biopsies from CLL, breast- and pancreatic- cancer patients suggest that this pathway may commonly be activated in a variety of malignancies.
Protein kinase c-β-dependent activation of NF-κB in stromal cells is indispensable for the survival of chronic lymphocytic leukemia B cells in vivo.
Specimen part
View SamplesTumor cell survival critically depends on heterotypic communication with benign cells in the microenvironment. Here we describe a novel survival signaling pathway activated in stromal cells by contact to B-cells from chronic lymphocytic leukemia (CLL) patients. The expression of PKC-II and the subsequent activation of NF-B in bone marrow stromal cells is a prerequisite to support the survival of malignant B-cells. PKC- knockout mice are insusceptible to CLL-transplantations, underscoring the in vivo significance of the PKC-II- NF-B signaling pathway in the tumor microenvironment. Upregulated stromal PKC-II in biopsies from CLL, breast- and pancreatic- cancer patients suggest that this pathway may commonly be activated in a variety of malignancies.
Protein kinase c-β-dependent activation of NF-κB in stromal cells is indispensable for the survival of chronic lymphocytic leukemia B cells in vivo.
Specimen part, Cell line
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ATF4 plays a pivotal role in the development of functional hematopoietic stem cells in mouse fetal liver.
Specimen part
View SamplesIn this study, we demonstrated that deletion of the activating transcription factor 4 (ATF4) resulted in severely impaired HSC expansion in the fetal liver at E12.5 and E15.5. In contrast, generation of the first HSC population in the aorta-gonad-mesonephros region at E11.5 was not significantly affected. Furthermore, the HSC-supporting ability of both endothelial and stromal cells in fetal liver was significantly compromised in the absence of ATF4. Gene profiling using RNA-seq revealed down-regulated expression of a panel of cytokines in ATF4-/- stromal cells, including angiopoietin-like protein 3 (Angptl3) and vascular endothelial growth factor-A (VEGFA).
ATF4 plays a pivotal role in the development of functional hematopoietic stem cells in mouse fetal liver.
Specimen part
View SamplesTGF-beta/Smads signaling plays important roles in vascular integrity. To identify potential Smad4 target genes in brain endothelial cells that control cerebrovascular integrity, the microarray assay was performed to compare the gene expression profiles of bEnd3 transfected with Smad4-siRNA and control-siRNA.
Endothelial Smad4 maintains cerebrovascular integrity by activating N-cadherin through cooperation with Notch.
Specimen part, Cell line
View SamplesNew insulin-producing pancreatic beta-cells are formed primarily by self-replication during adult life. To identify small molecules that can induce beta cell replication, a large chemical library was screened for proliferation of growth-arrested, reversibly immortalized mouse beta-cells using an automated high-throughput screening platform. A number of structurally diverse, active compounds were identified including phorbol esters, which likely act through protein kinase C, and a group of thiophene-pyrimidines that stimulate beta-cell proliferation by activating the Wnt signaling pathway. A group of dihydropyridine (DHP) derivatives was also shown to reversibly induce beta-cell replication in vitro by activating L-type calcium channels (LTCCs). Our data indicate that the LTCC agonist 2a affects the expression of genes involved in cell cycle progression and cellular proliferation. Furthermore, treatment of beta-cells with both LTCC agonist 2a and the Glp-1 receptor agonist Ex-4 showed an additive effect on beta-cell replication. The identification of small molecules that induce beta-cell proliferation suggests that it may be possible to reversibly expand other quiescent cells to overcome deficits associated with degenerative and/or autoimmune diseases.
Identification of small-molecule inducers of pancreatic beta-cell expansion.
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