Bradykinin-related peptides up-regulate the expression of kinin B1 and B2 receptor genes in human promonocytic cell line U937

Kinins, universal mediators of inflammation, are recognized by two kinds of receptors, B1 and B2, which have been found to be expressed in numerous cell types of several species. However, the knowledge of the regulation of these receptors in leukocytes is still not satisfactory. In the current work, we have demonstrated a constitutive production of B2 receptor mRNA in the human promonocyte U937 cells and its two-fold augmentation after cell differentiation with retinoic acid and phorbol ester. Bradykinin and des-Arg10-kallidin induced the expression of both B2 and B1 receptors in cells before and after differentiation. Generally, the undifferentiated cells were more susceptible to bradykinin-dependent induction of kinin receptors (increases by approximately 250% and 200% for B2 and B1 receptors, respectively). The induction, by approx. 200%, of B1 receptor by des-Arg10-kallidin was detected on both mRNA and protein levels. In addition, an unexpected strong induction of B2 receptor by this compound was observed in the retinoic acid- and phorbol ester-differentiated cells (by 150% and 200%, respectively) that suggests a possible autoregulation of kinin receptors by own agonists during the inflammatory state. On the other hand, a strong enhancement of the expression of both receptors by interleukin 1β, especially in the phorbol ester-differentiated cells, indicates the involvement of kinin receptors in the propagation of the inflammatory processes

EGF activates TTP expression by activation of ELK-1 and EGR-1 transcription factors

<p>Abstract</p> <p>Background</p> <p>Tristetraprolin (TTP) is a key mediator of processes such as inflammation resolution, the inhibition of autoimmunity and in cancer. It carries out this role by the binding and degradation of mRNA transcripts, thereby decreasing their half-life. Transcripts modulated by TTP encode proteins such as cytokines, pro-inflammatory agents and immediate-early response proteins. TTP can also modulate neoplastic phenotypes in many cancers. TTP is induced and functionally regulated by a spectrum of both pro- and anti-inflammatory cytokines, mitogens and drugs in a MAPK-dependent manner. So far the contribution of p38 MAPK to the regulation of TTP expression and function has been best described.</p> <p>Results</p> <p>Our results demonstrate the induction of the gene coding TTP (<it>ZFP36</it>) by EGF through the ERK1/2-dependent pathway and implicates the transcription factor ELK-1 in this process. We show that ELK-1 regulates <it>ZFP36 </it>expression by two mechanisms: by binding the <it>ZFP36 </it>promoter directly through ETS-binding site (+ 883 to +905 bp) and by inducing expression of EGR-1, which in turn increases <it>ZFP36 </it>expression through sequences located between -111 and -103 bp.</p> <p>Conclusions</p> <p>EGF activates TTP expression via ELK-1 and EGR-1 transcription factors.</p

Dynamic Gene Regulatory Networks Drive Hematopoietic Specification and Differentiation.

Metazoan development involves the successive activation and silencing of specific gene expression programs and is driven by tissue-specific transcription factors programming the chromatin landscape. To understand how this process executes an entire developmental pathway, we generated global gene expression, chromatin accessibility, histone modification, and transcription factor binding data from purified embryonic stem cell-derived cells representing six sequential stages of hematopoietic specification and differentiation. Our data reveal the nature of regulatory elements driving differential gene expression and inform how transcription factor binding impacts on promoter activity. We present a dynamic core regulatory network model for hematopoietic specification and demonstrate its utility for the design of reprogramming experiments. Functional studies motivated by our genome-wide data uncovered a stage-specific role for TEAD/YAP factors in mammalian hematopoietic specification. Our study presents a powerful resource for studying hematopoiesis and demonstrates how such data advance our understanding of mammalian development.This work was funded by a Longer Larger (LoLa) consortium grant from the Biotechnology and Biological Sciences Research Council, UK, to the senior authors and the corresponding author, computing infrastructure grants from the Wellcome Trust and National Institute for Health Research to B.G., grants from Cancer Research UK to G.L. and V.K., and funding from the Bloodwise charity to C.B.This is the final version of the article. It first appeared from Cell Press via http://dx.doi.org/10.1016/j.devcel.2016.01.02

Primitive erythrocytes are generated from hemogenic endothelial cells

AbstractPrimitive erythroblasts are the first blood cells generated during embryonic hematopoiesis. Tracking their emergence both in vivo and in vitro has remained challenging due to the lack of specific cell surface markers. To selectively investigate primitive erythropoiesis, we have engineered a new transgenic embryonic stem (ES) cell line, where eGFP expression is driven by the regulatory sequences of the embryonic βH1 hemoglobin gene expressed specifically in primitive erythroid cells. Using this ES cell line, we observed that the first primitive erythroblasts are detected in vitro around day 1.5 of blast colony differentiation, within the cell population positive for the early hematopoietic progenitor marker CD41. Moreover, we establish that these eGFP+ cells emerge from a hemogenic endothelial cell population similarly to their definitive hematopoietic counterparts. We further generated a corresponding βH1-eGFP transgenic mouse model and demonstrated the presence of a primitive erythroid primed hemogenic endothelial cell population in the developing embryo. Taken together, our findings demonstrate that both in vivo and in vitro primitive erythrocytes are generated from hemogenic endothelial cells.</jats:p

Concise Review:Recent Advances in the In Vitro Derivation of Blood Cell Populations

Hematopoietic cell-based therapies are currently available treatment options for many hematological and nonhematological disorders. However, the scarcity of allogeneic donor-derived cells is a major hurdle in treating these disorders. Embryonic stem cell-based directed differentiation and direct reprogramming of somatic cells provide excellent tools for the potential generation of hematopoietic stem cells usable in the clinic for cellular therapies. In addition to blood stem cell transplantation, mature blood cells such as red blood cells, platelets, and engineered T cells have also been increasingly used to treat several diseases. Besides cellular therapies, induced blood progenitor cells generated from autologous sources (either induced pluripotent stem cells or somatic cells) can be useful for disease modeling of bone marrow failures and acquired blood disorders. However, although great progress has been made toward these goals, we are still far from the use of in vitro-derived blood products in the clinic. We review the current state of knowledge on the directed differentiation of embryonic stem cells and the reprogramming of somatic cells toward the generation of blood stem cells and derivatives. SIGNIFICANCE: Hematopoietic cell-based therapies are currently available treatment options for many hematological and nonhematological disorders. However, the scarcity of allogeneic donor-derived cells is a major hurdle in treating these disorders. The current state of knowledge on the directed differentiation of embryonic stem cells and the reprogramming of somatic cells toward the generation of blood stem cells and derivatives is reviewed