Proceedings of The National Academy of Sciences, 2002
Early stages of B cell development take place in the bone marrow, resulting in formation of immat... more Early stages of B cell development take place in the bone marrow, resulting in formation of immature B cells, which migrate to the spleen for their final differentiation into mature cells. This final maturation step is essential for B cells to become responsive to antigens and to participate in the immune response. Previously, we showed that the MHC class II chaperone, invariant chain (Ii), controls the differentiation of B cells from the immature to the mature stage. In this study, by generating transgenic mice expressing truncated Ii lacking its luminal domain, we could dissect the chaperonin activity of Ii from its role in B cell maturation. We demonstrate in vivo that Ii N-terminal domain is directly involved in the maturation of B cells and is sufficient to promote B cell differentiation.
Exposure of pregnant women or animals to stress during a critical period of foetal brain developm... more Exposure of pregnant women or animals to stress during a critical period of foetal brain development increases the likelihood of anxiety, depression and learning deficits that are associated with structural alterations (such as a reduction in the length of dendrites) in the offspring hippocampus [1]. In a previous study we found that there is a downregulation of genes that play a role in synaptic vesicle release in prenatally stressed young female rats [2]. In the current study we are investigating the effect of prenatal stress on both female and male adult rats. In addition we are determining the difference of the proteomic profile of PS and C rats and the effect of stress on this profile using 2 dimension gel analysis. The purpose of this study is to elucidate the molecular mechanisms of long term effect of prenatal stress and to try to identify the differences of these mechanisms between males and females.
Exposure of pregnant women or animals to stress during a critical period of foetal brain developm... more Exposure of pregnant women or animals to stress during a critical period of foetal brain development increases the likelihood of anxiety, depression and learning deficits that are associated with structural alterations in the offspring hippocampus. In this study, we report the effect of gestational stress in rats on anxiogenic behaviour and hippocampal gene expression of their 23-day-old female offspring. As the rat brain continues to develop after birth, we also used the procedure of handling (H) during the first 10 days of life to reverse the anxiogenic behaviour of prenatally stressed (PS) rats. By means of micro-array analysis on hippocampal extracts, we found that the expression of about 6.1% of 9505 valid genes was significantly altered by prenatal stress (p < 0.05). Of these, 48% were over-expressed and 52% under-expressed. The latter included 300 genes that participate in axonal growth, regulation of ion channels and transporters, trafficking of synaptic vesicles and neurotransmitter release. About 30% of the genes that were down-regulated in PS rats were restored to control levels by H. These include genes that play a role in pre-synaptic organization and function. Our results provide a possible relationship between hippocampal gene expression and changes in behaviour resulting from prenatal stress.
Objective: To examine gene expression profiles of women conceiving spontaneously after the age of... more Objective: To examine gene expression profiles of women conceiving spontaneously after the age of 45. Design: Expression profiling by complementary DNA microarray analysis. Setting: University departments. Patient(s): Eight women 45 years or older (study group) who conceived spontaneously and were 6 months after their last delivery were compared with six women aged 45 years old (control group) who had their last delivery before the age of 30. Intervention(s): Blood samples were collected from each woman for RNA isolation from peripheral blood mononuclear cells (PBMC). Main Outcome Measure(s): Expression profiles of PBMC isolated from each woman were determined by using Affymetrix DNA microarray analysis covering about 15,000 identified genes. Result(s): Microarray of global gene expression revealed 671 genes that showed statistically significant differential expression between the study and control groups: 383 genes were overexpressed and 288 were underexpressed. The most significant functional groups defining these genes were: apoptosis, ubiquitination, and energy production. As many as 60 genes also participated in ovarian physiology. Conclusion(s): These observations suggest that extended fertility is associated with a unique ability to enrich cellular processes, leading to delayed ovarian senescence. (Fertil Steril Ò 2008;-:---.
The embryonal carcinoma P19 cells provide a model to study neuronal differentiation. Cells that a... more The embryonal carcinoma P19 cells provide a model to study neuronal differentiation. Cells that are exposed to retinoic acid become mature neurons within a few days with a pronounced axonal and dendritic polarity. Notably, an accelerated rate of neurite extension characterizes densely but not sparsely plated cells. DNA microarray experiments show maximal differences in gene expression of the dense compared to sparse plated cultures at 18 h after plating. The differentially expressed genes are enriched by functions of cell adhesion and cytoskeletal regulation. Doublecortin, Lis1, Reelin, Map2 and dozens of proteins that regulate cytoskeleton dynamics increase in concordance with a rapid neurite extension. A brief elevation in intracellular cAMP via PKA is sufficient to instigate the phenotype of accelerated neurite extension with no effect on P19 cell fate. Furthermore, we show that the cAMP dependent changes in the expression of cytoskeleton regulators such as doublecortin are restricted to a short time window prior to the establishment of functional neurons. We propose that the wave of gene expression of cytoskeletal regulators that is accompanied by accelerated neurite extension acts in remodeling young developing neurons in the CNS.
Embryonal carcinoma P19 cells provide an ideal model to study molecular programs along differenti... more Embryonal carcinoma P19 cells provide an ideal model to study molecular programs along differentiation. Upon induction by retinoic acid (RA), the cells undergo a program of differentiation that generates functioning neurons within 60 h. RA induced cells that were plated as sparse (1000 cells/mm2) or dense (4000 cells/mm2) cultures showed a marked difference in the culture morphology with the dense cultures exhibiting rapid maturation and accelerated neurite outgrowth. The protein expression levels of the sparse and dense cultures were compared 48 h following RA. Cell extracts were separated by 1-DE and 2-DE and differential expression (>four-fold) proteins were identified by MS. Here, we focus on 20 proteins associated with cytoskeletal regulation and stress-dependent protein refolding. The first group includes drebrin, cofilin, α-internexin, vimentin, and nestin. Among the proteins in the second group are subunits of the TCP-1, and several chaperones of the Hsp70 and Hsp90 families. We show that coordinated remodeling of the cytoskeleton and modulations in chaperone activity underlie the change in neurite extension rate. Furthermore, a proteomics-based analysis applied on P19 neurons demonstrated pathways underlying neuronal outgrowth, suggesting that a malfunction of such pathways leads to neuropathological conditions.
Proceedings of The National Academy of Sciences, 2002
Early stages of B cell development take place in the bone marrow, resulting in formation of immat... more Early stages of B cell development take place in the bone marrow, resulting in formation of immature B cells, which migrate to the spleen for their final differentiation into mature cells. This final maturation step is essential for B cells to become responsive to antigens and to participate in the immune response. Previously, we showed that the MHC class II chaperone, invariant chain (Ii), controls the differentiation of B cells from the immature to the mature stage. In this study, by generating transgenic mice expressing truncated Ii lacking its luminal domain, we could dissect the chaperonin activity of Ii from its role in B cell maturation. We demonstrate in vivo that Ii N-terminal domain is directly involved in the maturation of B cells and is sufficient to promote B cell differentiation.
Exposure of pregnant women or animals to stress during a critical period of foetal brain developm... more Exposure of pregnant women or animals to stress during a critical period of foetal brain development increases the likelihood of anxiety, depression and learning deficits that are associated with structural alterations (such as a reduction in the length of dendrites) in the offspring hippocampus [1]. In a previous study we found that there is a downregulation of genes that play a role in synaptic vesicle release in prenatally stressed young female rats [2]. In the current study we are investigating the effect of prenatal stress on both female and male adult rats. In addition we are determining the difference of the proteomic profile of PS and C rats and the effect of stress on this profile using 2 dimension gel analysis. The purpose of this study is to elucidate the molecular mechanisms of long term effect of prenatal stress and to try to identify the differences of these mechanisms between males and females.
Exposure of pregnant women or animals to stress during a critical period of foetal brain developm... more Exposure of pregnant women or animals to stress during a critical period of foetal brain development increases the likelihood of anxiety, depression and learning deficits that are associated with structural alterations in the offspring hippocampus. In this study, we report the effect of gestational stress in rats on anxiogenic behaviour and hippocampal gene expression of their 23-day-old female offspring. As the rat brain continues to develop after birth, we also used the procedure of handling (H) during the first 10 days of life to reverse the anxiogenic behaviour of prenatally stressed (PS) rats. By means of micro-array analysis on hippocampal extracts, we found that the expression of about 6.1% of 9505 valid genes was significantly altered by prenatal stress (p < 0.05). Of these, 48% were over-expressed and 52% under-expressed. The latter included 300 genes that participate in axonal growth, regulation of ion channels and transporters, trafficking of synaptic vesicles and neurotransmitter release. About 30% of the genes that were down-regulated in PS rats were restored to control levels by H. These include genes that play a role in pre-synaptic organization and function. Our results provide a possible relationship between hippocampal gene expression and changes in behaviour resulting from prenatal stress.
Objective: To examine gene expression profiles of women conceiving spontaneously after the age of... more Objective: To examine gene expression profiles of women conceiving spontaneously after the age of 45. Design: Expression profiling by complementary DNA microarray analysis. Setting: University departments. Patient(s): Eight women 45 years or older (study group) who conceived spontaneously and were 6 months after their last delivery were compared with six women aged 45 years old (control group) who had their last delivery before the age of 30. Intervention(s): Blood samples were collected from each woman for RNA isolation from peripheral blood mononuclear cells (PBMC). Main Outcome Measure(s): Expression profiles of PBMC isolated from each woman were determined by using Affymetrix DNA microarray analysis covering about 15,000 identified genes. Result(s): Microarray of global gene expression revealed 671 genes that showed statistically significant differential expression between the study and control groups: 383 genes were overexpressed and 288 were underexpressed. The most significant functional groups defining these genes were: apoptosis, ubiquitination, and energy production. As many as 60 genes also participated in ovarian physiology. Conclusion(s): These observations suggest that extended fertility is associated with a unique ability to enrich cellular processes, leading to delayed ovarian senescence. (Fertil Steril Ò 2008;-:---.
The embryonal carcinoma P19 cells provide a model to study neuronal differentiation. Cells that a... more The embryonal carcinoma P19 cells provide a model to study neuronal differentiation. Cells that are exposed to retinoic acid become mature neurons within a few days with a pronounced axonal and dendritic polarity. Notably, an accelerated rate of neurite extension characterizes densely but not sparsely plated cells. DNA microarray experiments show maximal differences in gene expression of the dense compared to sparse plated cultures at 18 h after plating. The differentially expressed genes are enriched by functions of cell adhesion and cytoskeletal regulation. Doublecortin, Lis1, Reelin, Map2 and dozens of proteins that regulate cytoskeleton dynamics increase in concordance with a rapid neurite extension. A brief elevation in intracellular cAMP via PKA is sufficient to instigate the phenotype of accelerated neurite extension with no effect on P19 cell fate. Furthermore, we show that the cAMP dependent changes in the expression of cytoskeleton regulators such as doublecortin are restricted to a short time window prior to the establishment of functional neurons. We propose that the wave of gene expression of cytoskeletal regulators that is accompanied by accelerated neurite extension acts in remodeling young developing neurons in the CNS.
Embryonal carcinoma P19 cells provide an ideal model to study molecular programs along differenti... more Embryonal carcinoma P19 cells provide an ideal model to study molecular programs along differentiation. Upon induction by retinoic acid (RA), the cells undergo a program of differentiation that generates functioning neurons within 60 h. RA induced cells that were plated as sparse (1000 cells/mm2) or dense (4000 cells/mm2) cultures showed a marked difference in the culture morphology with the dense cultures exhibiting rapid maturation and accelerated neurite outgrowth. The protein expression levels of the sparse and dense cultures were compared 48 h following RA. Cell extracts were separated by 1-DE and 2-DE and differential expression (>four-fold) proteins were identified by MS. Here, we focus on 20 proteins associated with cytoskeletal regulation and stress-dependent protein refolding. The first group includes drebrin, cofilin, α-internexin, vimentin, and nestin. Among the proteins in the second group are subunits of the TCP-1, and several chaperones of the Hsp70 and Hsp90 families. We show that coordinated remodeling of the cytoskeleton and modulations in chaperone activity underlie the change in neurite extension rate. Furthermore, a proteomics-based analysis applied on P19 neurons demonstrated pathways underlying neuronal outgrowth, suggesting that a malfunction of such pathways leads to neuropathological conditions.
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Papers by Yoel Bogoch