Nurit Cohen - Academia.edu (original) (raw)

Papers by Nurit Cohen

Placenta, 2013

The first step in human implantation is the attraction of the blastocyst to the endometrium. We a... more The first step in human implantation is the attraction of the blastocyst to the endometrium. We aimed to study attraction of the human blastocyst to the endometrium, and how this process is accomplished by chemokines secreted by the endometrium. Blastocyst trophectoderm cells and other trophoblast lineage cells were subjected to attraction assays by IP-10 and other chemokines using transwell migration and chemotaxis assays. Chemokine expression and secretion were investigated using immunohistochemistry, ELISA, FACS analysis, and RT-PCR on material from flushing of the uterine cavity in endometrial biopsies. Chemokine receptor expression by blastocyst trophectoderm following PGD biopsy, trophectoderm derived from hES, placental villi, and other trophoblast lineage cells were characterized by the same methods. IP-10 dramatically attracted trophectoderm derived from hES cells and other lineages by interaction with CXCR3 chemokine receptors, as shown by both chemotaxis and transwell migration. High levels of IP-10 were detected throughout the menstrual cycle at flushing of the uterine cavity. Immunohistochemistry, FACS analysis, and RT-PCR of endometrial biopsy detected IP-10 in glandular and stromal cells of the endometrium. High levels of IP-10 were detected in condition medium of the endometrial stromal and glandular cells. Of all of the chemokine/chemokine receptor combinations examined, the IP-10/CXCR3 interaction was the only cytokine that was significantly elevated. While they await the wandering blastocyst, IP-10 is produced by many cells of the endometrium, but not by endometrial natural killer cells. Endometrial IP-10 may specifically attract human blastocyst trophectoderm cells early in implantation.

European Journal of Immunology, 2001

Anti-DNA autoantibodies are the hallmark of human and murine systemic lupus erythematosus (SLE), ... more Anti-DNA autoantibodies are the hallmark of human and murine systemic lupus erythematosus (SLE), an autoimmune rheumatic disease of unknown etiology. Some of these antibodies are believed to be pathogenic for kidney tissue and to initiate immune glomerulonephritis. However, the mechanisms by which anti-DNA antibodies participate in tissue injury remain controversial. We have studied the in vivo pathogenicity of anti-DNA monoclonal antibodies in immune deficient mice, using a panel of murine B cell hybridomas. No consistent genetic or immunochemical differences were found between pathogenic and non-pathogenic anti-DNA antibodies. However, the two antibody populations differed in their cross-reaction with the acidic actin-binding protein, §-actinin, that is known to play a major role in the structural integrity of glomerular filtration components. These results suggest that kidney dysfunction in SLE may be facilitated by protein-nucleic acid antigenic mimicry.

European Journal of Immunology, 2002

Anti-DNA knock-in mice serve as models for studying B cell tolerance mechanisms to a ubiquitous a... more Anti-DNA knock-in mice serve as models for studying B cell tolerance mechanisms to a ubiquitous antigen. We have constructed six strains of double transgenic (C57BL/6×BALB/ c)F1 mice, each expressing an unmutated or somatically mutated anti-DNA heavy (H) chain, combined with one of three different light (L) chains, namely V ‹ 1-J ‹ 1, V ‹ 4-J ‹ 4 and V ‹ 8-J ‹ 5. In vitro analysis of the various Ig H/L chain combinations showed that all had a similar specificity for single-stranded DNA and double-stranded DNA, but that antibodies encoded by the mutated H chain had higher affinities for the autoantigen. None of the targeted mouse strains exhibited significant levels of serum anti-DNA activity. However, while B cells from mice carrying the V ‹ 1-J ‹ 1 transgenic L chains were tolerized almost exclusively by L chain receptor editing in an affinity-independent manner, the mice expressing V ‹ 8-J ‹ 5 L chains have utilized affinity-dependent clonal anergy as their sole mechanism of B cell tolerance. V ‹ 4-J ‹ 4 targeted mice exhibited an intermediate phenotype with respect to these two mechanisms of B cell tolerance. Our results suggest that receptor editing is the preferred mechanism of B cell tolerance and that the efficiency of L chain editing is directly related to the number of available J ‹ segments on the expressed V ‹ allele.

The Journal of Immunology, 2010

Human embryonic stem cells (hESCs) can proliferate extensively in culture and give rise to progen... more Human embryonic stem cells (hESCs) can proliferate extensively in culture and give rise to progeny of the three germ layers. Several reports suggested that mouse and hESCs may attenuate immune responses. In this study, we focused on the mechanism by which hESCs inhibit T cell responses. Using coculture experiments, we demonstrate that hESCs inhibit cytokine secretion and T cell proliferation in response to potent T cell activators. Furthermore, we show that hESCs downmodulate the TCR-associated CD3-z chain. These effects are maintained when hESCs are replaced by their conditioned media and can be restored by the addition of L-arginine to hESC-conditioned media or by treatment of hESCs with a specific arginase inhibitor. Moreover, we show arginase-I expression and activity in hESCs. We further demonstrate that mouse ESCs (mESCs) similarly inhibit T cell activation via arginase I, suggesting an evolutionary conserved mechanism of T cell suppression by ESCs. In addition, we demonstrate that arginase I expression is not limited to ESCs in culture, but can also be detected in the inner cell mass and the trophectoderm of preimplantation mouse embryos and hESC-derived trophectoderm cells. Finally, T cells infiltrating ESC-derived teratomas have significantly lower levels of CD3-z chain. Collectively, the data indicate a role for ESC-arginase I activity in the attenuation of T cell activation.

European Journal of Immunology, 2003

We have previously constructed knock-in (C57BL/6×BALB/c) F1 mice, each expressing an anti-DNA hea... more We have previously constructed knock-in (C57BL/6×BALB/c) F1 mice, each expressing an anti-DNA heavy (H) chain (D42), combined with one of three different light (L) chains, namely Vκ1-Jκ1, Vκ4-Jκ4 or Vκ8-Jκ5. All of these H/L chain combinations bind DNA with similar affinity and fine specificity. However, while mice carrying Vκ1-Jκ1-transgenic L chain were tolerized almost exclusively by L chain receptor editing, the mice expressing Vκ8-Jκ5 L chains utilized clonal anergy as their principal mechanism of B cell tolerance. Vκ4-Jκ4 targeted mice exhibited an intermediate phenotype. In the present study, these three H/L chain combinations were backcrossed onto the autoimmune NZB/NZW F1 mice. We find that the mechanism of clonal anergy is abrogated in these mice, but that receptor editing is maintained. Moreover, diseased NZB/NZW mice utilize L chain secondary rearrangements for the generation of high-affinity, anti-dsDNA-producing B cells from low-affinity precursors. The edited B cell clones are not deleted or anergized in the autoimmune animal; rather they are selected for activation, class-switching and affinity maturation by somatic mutation. These results suggest that B cell receptor editing plays an important role not only in tolerance induction, but also in generating high-affinity autoreactive B cells in autoimmune diseases.

European Journal of Immunology, 2006

CD22-deficient mice are characterized by B cell hyperactivity and autoimmunity. We have construct... more CD22-deficient mice are characterized by B cell hyperactivity and autoimmunity. We have constructed knock-in CD22–/– mice, expressing an anti-DNA heavy (H) chain (D42), alone or combined with Vκ1-Jκ1 or Vκ8-Jκ5 light (L) chains. The Ig-targeted mice produced a lupus-like serology that was age- and sex-dependent. High-affinity IgG autoantibodies were largely dependent on the selection of B cells with a particular H/L combination, in which a non-transgenic, endogenous L chain was assembled by secondary rearrangements through the mechanism of receptor editing. Moreover, we present evidence that these secondary rearrangements are very prominent in splenic peripheral B cells. Since CD22 is primarily expressed on the surface of peripheral B cells, we propose a model for the development of a lupus-like autoimmune disease by a combination of peripheral receptor editing and abnormal B cell activation.

Cell Stem Cell, 2009

Understanding how neuronal diversity is achieved within the cerebral cortex remains a major chall... more Understanding how neuronal diversity is achieved within the cerebral cortex remains a major challenge in neuroscience. The advent of human embryonic stem cells (hESCs) as a model system provides a unique opportunity to study human corticogenesis in vitro and to identify the mechanisms that promote neuronal differentiation to achieve neuronal diversity in human brain. The transcription factor Fezf2 is necessary and sufficient for the specification of subcerebral projection neurons in mouse. However, its function during human corticogenesis is poorly understood. This study reports the differentiation of a hFezf2-YFP hESC reporter line into corticofugal projection neurons capable of extending axons toward the spinal cord upon transplantation into neonatal mouse brains. Additionally, we show that triple inhibition of the TGFß/ BMP/Wnt-Shh pathway promotes the generation of hFezf2-expressing cells in vitro. Finally, this study unveils the isolation of two novel and distinct populations of hFezf2-YFP expressing cells reminiscent of the distinct Fezf2-expressing neuronal subtypes in the developing mouse brain. Overall our data suggest that the directed differentiation of hESCs into corticofugal neurons provides a useful model to identify the molecular mechanisms regulating human corticofugal differentiation and survival.

Placenta, 2013

The first step in human implantation is the attraction of the blastocyst to the endometrium. We a... more The first step in human implantation is the attraction of the blastocyst to the endometrium. We aimed to study attraction of the human blastocyst to the endometrium, and how this process is accomplished by chemokines secreted by the endometrium. Blastocyst trophectoderm cells and other trophoblast lineage cells were subjected to attraction assays by IP-10 and other chemokines using transwell migration and chemotaxis assays. Chemokine expression and secretion were investigated using immunohistochemistry, ELISA, FACS analysis, and RT-PCR on material from flushing of the uterine cavity in endometrial biopsies. Chemokine receptor expression by blastocyst trophectoderm following PGD biopsy, trophectoderm derived from hES, placental villi, and other trophoblast lineage cells were characterized by the same methods. IP-10 dramatically attracted trophectoderm derived from hES cells and other lineages by interaction with CXCR3 chemokine receptors, as shown by both chemotaxis and transwell migration. High levels of IP-10 were detected throughout the menstrual cycle at flushing of the uterine cavity. Immunohistochemistry, FACS analysis, and RT-PCR of endometrial biopsy detected IP-10 in glandular and stromal cells of the endometrium. High levels of IP-10 were detected in condition medium of the endometrial stromal and glandular cells. Of all of the chemokine/chemokine receptor combinations examined, the IP-10/CXCR3 interaction was the only cytokine that was significantly elevated. While they await the wandering blastocyst, IP-10 is produced by many cells of the endometrium, but not by endometrial natural killer cells. Endometrial IP-10 may specifically attract human blastocyst trophectoderm cells early in implantation.

European Journal of Immunology, 2001

Anti-DNA autoantibodies are the hallmark of human and murine systemic lupus erythematosus (SLE), ... more Anti-DNA autoantibodies are the hallmark of human and murine systemic lupus erythematosus (SLE), an autoimmune rheumatic disease of unknown etiology. Some of these antibodies are believed to be pathogenic for kidney tissue and to initiate immune glomerulonephritis. However, the mechanisms by which anti-DNA antibodies participate in tissue injury remain controversial. We have studied the in vivo pathogenicity of anti-DNA monoclonal antibodies in immune deficient mice, using a panel of murine B cell hybridomas. No consistent genetic or immunochemical differences were found between pathogenic and non-pathogenic anti-DNA antibodies. However, the two antibody populations differed in their cross-reaction with the acidic actin-binding protein, §-actinin, that is known to play a major role in the structural integrity of glomerular filtration components. These results suggest that kidney dysfunction in SLE may be facilitated by protein-nucleic acid antigenic mimicry.

European Journal of Immunology, 2002

Anti-DNA knock-in mice serve as models for studying B cell tolerance mechanisms to a ubiquitous a... more Anti-DNA knock-in mice serve as models for studying B cell tolerance mechanisms to a ubiquitous antigen. We have constructed six strains of double transgenic (C57BL/6×BALB/ c)F1 mice, each expressing an unmutated or somatically mutated anti-DNA heavy (H) chain, combined with one of three different light (L) chains, namely V ‹ 1-J ‹ 1, V ‹ 4-J ‹ 4 and V ‹ 8-J ‹ 5. In vitro analysis of the various Ig H/L chain combinations showed that all had a similar specificity for single-stranded DNA and double-stranded DNA, but that antibodies encoded by the mutated H chain had higher affinities for the autoantigen. None of the targeted mouse strains exhibited significant levels of serum anti-DNA activity. However, while B cells from mice carrying the V ‹ 1-J ‹ 1 transgenic L chains were tolerized almost exclusively by L chain receptor editing in an affinity-independent manner, the mice expressing V ‹ 8-J ‹ 5 L chains have utilized affinity-dependent clonal anergy as their sole mechanism of B cell tolerance. V ‹ 4-J ‹ 4 targeted mice exhibited an intermediate phenotype with respect to these two mechanisms of B cell tolerance. Our results suggest that receptor editing is the preferred mechanism of B cell tolerance and that the efficiency of L chain editing is directly related to the number of available J ‹ segments on the expressed V ‹ allele.

The Journal of Immunology, 2010

Human embryonic stem cells (hESCs) can proliferate extensively in culture and give rise to progen... more Human embryonic stem cells (hESCs) can proliferate extensively in culture and give rise to progeny of the three germ layers. Several reports suggested that mouse and hESCs may attenuate immune responses. In this study, we focused on the mechanism by which hESCs inhibit T cell responses. Using coculture experiments, we demonstrate that hESCs inhibit cytokine secretion and T cell proliferation in response to potent T cell activators. Furthermore, we show that hESCs downmodulate the TCR-associated CD3-z chain. These effects are maintained when hESCs are replaced by their conditioned media and can be restored by the addition of L-arginine to hESC-conditioned media or by treatment of hESCs with a specific arginase inhibitor. Moreover, we show arginase-I expression and activity in hESCs. We further demonstrate that mouse ESCs (mESCs) similarly inhibit T cell activation via arginase I, suggesting an evolutionary conserved mechanism of T cell suppression by ESCs. In addition, we demonstrate that arginase I expression is not limited to ESCs in culture, but can also be detected in the inner cell mass and the trophectoderm of preimplantation mouse embryos and hESC-derived trophectoderm cells. Finally, T cells infiltrating ESC-derived teratomas have significantly lower levels of CD3-z chain. Collectively, the data indicate a role for ESC-arginase I activity in the attenuation of T cell activation.

European Journal of Immunology, 2003

We have previously constructed knock-in (C57BL/6×BALB/c) F1 mice, each expressing an anti-DNA hea... more We have previously constructed knock-in (C57BL/6×BALB/c) F1 mice, each expressing an anti-DNA heavy (H) chain (D42), combined with one of three different light (L) chains, namely Vκ1-Jκ1, Vκ4-Jκ4 or Vκ8-Jκ5. All of these H/L chain combinations bind DNA with similar affinity and fine specificity. However, while mice carrying Vκ1-Jκ1-transgenic L chain were tolerized almost exclusively by L chain receptor editing, the mice expressing Vκ8-Jκ5 L chains utilized clonal anergy as their principal mechanism of B cell tolerance. Vκ4-Jκ4 targeted mice exhibited an intermediate phenotype. In the present study, these three H/L chain combinations were backcrossed onto the autoimmune NZB/NZW F1 mice. We find that the mechanism of clonal anergy is abrogated in these mice, but that receptor editing is maintained. Moreover, diseased NZB/NZW mice utilize L chain secondary rearrangements for the generation of high-affinity, anti-dsDNA-producing B cells from low-affinity precursors. The edited B cell clones are not deleted or anergized in the autoimmune animal; rather they are selected for activation, class-switching and affinity maturation by somatic mutation. These results suggest that B cell receptor editing plays an important role not only in tolerance induction, but also in generating high-affinity autoreactive B cells in autoimmune diseases.

European Journal of Immunology, 2006

CD22-deficient mice are characterized by B cell hyperactivity and autoimmunity. We have construct... more CD22-deficient mice are characterized by B cell hyperactivity and autoimmunity. We have constructed knock-in CD22–/– mice, expressing an anti-DNA heavy (H) chain (D42), alone or combined with Vκ1-Jκ1 or Vκ8-Jκ5 light (L) chains. The Ig-targeted mice produced a lupus-like serology that was age- and sex-dependent. High-affinity IgG autoantibodies were largely dependent on the selection of B cells with a particular H/L combination, in which a non-transgenic, endogenous L chain was assembled by secondary rearrangements through the mechanism of receptor editing. Moreover, we present evidence that these secondary rearrangements are very prominent in splenic peripheral B cells. Since CD22 is primarily expressed on the surface of peripheral B cells, we propose a model for the development of a lupus-like autoimmune disease by a combination of peripheral receptor editing and abnormal B cell activation.

Cell Stem Cell, 2009

Understanding how neuronal diversity is achieved within the cerebral cortex remains a major chall... more Understanding how neuronal diversity is achieved within the cerebral cortex remains a major challenge in neuroscience. The advent of human embryonic stem cells (hESCs) as a model system provides a unique opportunity to study human corticogenesis in vitro and to identify the mechanisms that promote neuronal differentiation to achieve neuronal diversity in human brain. The transcription factor Fezf2 is necessary and sufficient for the specification of subcerebral projection neurons in mouse. However, its function during human corticogenesis is poorly understood. This study reports the differentiation of a hFezf2-YFP hESC reporter line into corticofugal projection neurons capable of extending axons toward the spinal cord upon transplantation into neonatal mouse brains. Additionally, we show that triple inhibition of the TGFß/ BMP/Wnt-Shh pathway promotes the generation of hFezf2-expressing cells in vitro. Finally, this study unveils the isolation of two novel and distinct populations of hFezf2-YFP expressing cells reminiscent of the distinct Fezf2-expressing neuronal subtypes in the developing mouse brain. Overall our data suggest that the directed differentiation of hESCs into corticofugal neurons provides a useful model to identify the molecular mechanisms regulating human corticofugal differentiation and survival.