1,721,116 research outputs found
Nuclear association of tyrosine-phosphorylated Vav to phospholipase C-gamma1 and phosphoinositide 3-kinase during granulocytic differentiation of HL-60 cells.
No full textThe granulocytic differentiation of HL-60 cells induced by all-trans retinoic acid was accompanied by a progressive tyrosine phosphorylation of specific proteins in either cells or isolated nuclei. Among these phosphoproteins, we identified the Vav adaptor in whole cells as well as in the inner nuclear compartment, where the increase in its tyrosine phosphorylation level was more conspicuous. We also demonstrated the differentiation-dependent association of nuclear phosphorylated Vav to phospholipase C-gamma1 and to the p85 regulatory subunit of phosphoinositide 3-kinase. The role of the Vav/phospholipase C-gamma1/phosphoinositide 3-kinase phosphoprotein complexes in the nuclei of HL-60 induced to differentiate along the granulocytic lineage is discussed
The Link Among Neurological Diseases: Extracellular Vesicles as a Possible Brain Injury Footprint
No full textExtracellular vesicles (EVs), referred as membranous vesicles released into body fluids from all cell types, represent a novel model to explain some aspects of the inter-cellular cross talk. It has been demonstrated that the EVs modify the phenotype of target cells, acting through a large spectrum of mechanisms. In the central nervous system, the EVs are responsible of the wide range of physiological processes required for normal brain function and neuronal support, such as immune signaling, cellular proliferation, differentiation, and senescence. Growing evidences link the EV functions to the pathogenic machinery of the neurological diseases, contributing to the disease progression and spreading. Extracellular vesicles are involved in the brain injury by multimodal ways; they propagate inflammation across the blood brain barrier (BBB), mediate neuroprotection and modulate regenerative processes. For these reasons, extracellular vesicles represent a promising biomarker in neurological disorders as well as an interesting starting point for the development of novel therapeutic strategies. Herein, we review the role of the EVs in the pathogenesis of neurological disease, discussing their potential clinical applications
Intranuclear translocation of phospholipase C β2 during HL-60 myeloid differentiation
No full textPhospholipases C (PLC) beta3, gamma1, and gamma2 were detected in nuclei of HL-60 promyelocitic leukaemia cells. When HL-60 cells undergo terminal myeloid differentiation in the presence of ATRA, the beta2 isoform appeared inside nuclei and was up-regulated until 72 hours of ATRA treatment. The beta3 isozyme was also increased until 72 hours and both isoforms lowered their intranuclear amount at 96 hours and following days of treatment. By contrast PLC gamma1 and gamma2 progressively increased in the nucleus during granulocytic differentiation even after 72 hours of treatment. Terminal differentiation was characterised by the expression of high levels of PLC gamma1 and gamma2 and by low levels of PLC beta2 and beta3 in the nucleus. PIP2 and PIP hydrolysis paralleled the prevalence of the beta or gamma subfamily, respectively. Moreover, at all the examined times no changes of PLCs in the whole cell were detectable, indicating a de novo nuclear translocation of the beta2 and an increased accumulation of beta3, gamma1, and gamma2 isoforms. Thus, the intranuclear presence, expression, and activity of PLC isozymes, which are modulated during differentiation of HL-60 cells, implicate a role for nuclear phosphoinositide signalling in the process of cell maturation. In particular the nuclear translocation of PLC beta2 candidates this PLC as a key enzyme in the granulocytic differentiative commitment of HL-60 cells
Phosphoinositide 3-kinase activity is essential for all-trans-retinoic acid-induced granulocytic differentiation of HL-60 cells.
No full textPhosphoinositide 3-kinase (PI 3-K) activity increases in HL-60 cells that are induced to granulocytic differentiation by all-trans-retinoic acid. Immunochemical and immunocytochemical analyses by confocal microscopy also reveal an increase in the amount of the enzyme, which is particularly evident at the nuclear level. Inhibition of PI 3-K activity by nanomolar concentrations of wortmannin and of its expression by transfection with an antisense fragment of p85alpha prevented the differentiative process. The data obtained indicate that PI 3-K activity plays an essential role in promoting granulocytic differentiation
Monocytic differentiation of HL-60 cells is characterized by the nuclear translocation of phosphatidylinositol 3-kinase and of definite phosphatidylinositol-specific phospholipase C isoforms.
No full textImmunochemical and immunocytochemical data indicate that nuclei of HL-60 cells contain different enzymes involved in the phosphoinositide cycle, such as PI 3-K and the phosphatidylinositol-specific PLC isoforms beta3, gamma1 and gamma2. These enzymes translocate differently to the nuclear fraction when HL-60 cells are treated with differentiating doses of vitamin D3: PI 3-K translocated progressively to the nucleus in parallel with full differentiation until 96 hours. PLC beta3 increased until 72 hours of treatment and then lowered its intranuclear amount and PLC gamma1 was unchanged at all the examined times. PLC gamma2 nuclear translocation increased progressively until 96 hours of vitamin D3 administration. A fourth PLC isozyme, beta2, present in the cytoplasm of untreated cells, translocates to the cytoplasm after vitamin D3 addition and reaches the highest concentration at the end of monocytic differentiation. Terminal monocytic differentiation was characterized at the nuclear level by high levels of PI 3-K and PLC gamma2 and by the novel expression of PLC beta2. We then observed that the xi isoform of PKC, constitutively present in nuclei of HL-60 cells, translocated to the nucleus when cells were induced to differentiate along the monocytic lineage, but the nuclear translocation of PKC xi was blocked as a consequence of PI 3-K inhibition by Wortmannin. These findings indicate that the main components of the noncanonical and canonical inositol lipid signal transduction pathways, including PI 3-K, PLC beta2 and beta3, PLC gamma2, undergo nuclear translocation and may therefore play a relevant role during monocytic differentiation at the nuclear level. Furthermore, PKC xi nuclear translocation appears to be related to PI 3-K activity
Intranuclear translocation of phospholipase C beta2 during HL-60 myeloid differentiation.
No full textPhospholipases C (PLC) beta3, gamma1, and gamma2 were detected in nuclei of HL-60 promyelocitic leukaemia cells. When HL-60 cells undergo terminal myeloid differentiation in the presence of ATRA, the beta2 isoform appeared inside nuclei and was up-regulated until 72 hours of ATRA treatment. The beta3 isozyme was also increased until 72 hours and both isoforms lowered their intranuclear amount at 96 hours and following days of treatment. By contrast PLC gamma1 and gamma2 progressively increased in the nucleus during granulocytic differentiation even after 72 hours of treatment. Terminal differentiation was characterised by the expression of high levels of PLC gamma1 and gamma2 and by low levels of PLC beta2 and beta3 in the nucleus. PIP2 and PIP hydrolysis paralleled the prevalence of the beta or gamma subfamily, respectively. Moreover, at all the examined times no changes of PLCs in the whole cell were detectable, indicating a de novo nuclear translocation of the beta2 and an increased accumulation of beta3, gamma1, and gamma2 isoforms. Thus, the intranuclear presence, expression, and activity of PLC isozymes, which are modulated during differentiation of HL-60 cells, implicate a role for nuclear phosphoinositide signalling in the process of cell maturation. In particular the nuclear translocation of PLC beta2 candidates this PLC as a key enzyme in the granulocytic differentiative commitment of HL-60 cells
Monocytic differentiation of HL-60 cells is characterized by the nuclear translocation of phosphatidylinositol 3-kinase and of definite phosphatidylinositol-specific phospholipase C isoforms.
No full textImmunochemical and immunocytochemical data indicate that nuclei of HL-60 cells contain different enzymes involved in the phosphoinositide cycle, such as PI 3-K and the phosphatidylinositol-specific PLC isoforms beta3, gamma1 and gamma2. These enzymes translocate differently to the nuclear fraction when HL-60 cells are treated with differentiating doses of vitamin D3: PI 3-K translocated progressively to the nucleus in parallel with full differentiation until 96 hours. PLC beta3 increased until 72 hours of treatment and then lowered its intranuclear amount and PLC gamma1 was unchanged at all the examined times. PLC gamma2 nuclear translocation increased progressively until 96 hours of vitamin D3 administration. A fourth PLC isozyme, beta2, present in the cytoplasm of untreated cells, translocates to the cytoplasm after vitamin D3 addition and reaches the highest concentration at the end of monocytic differentiation. Terminal monocytic differentiation was characterized at the nuclear level by high levels of PI 3-K and PLC gamma2 and by the novel expression of PLC beta2. We then observed that the xi isoform of PKC, constitutively present in nuclei of HL-60 cells, translocated to the nucleus when cells were induced to differentiate along the monocytic lineage, but the nuclear translocation of PKC xi was blocked as a consequence of PI 3-K inhibition by Wortmannin. These findings indicate that the main components of the noncanonical and canonical inositol lipid signal transduction pathways, including PI 3-K, PLC beta2 and beta3, PLC gamma2, undergo nuclear translocation and may therefore play a relevant role during monocytic differentiation at the nuclear level. Furthermore, PKC xi nuclear translocation appears to be related to PI 3-K activity
Nuclear association of tyrosine-phosphorylated Vav to phospholipase C-gamma1 and phosphoinositide 3-kinase during granulocytic differentiation of HL-60 cells.
No full textThe granulocytic differentiation of HL-60 cells induced by all-trans retinoic acid was accompanied by a progressive tyrosine phosphorylation of specific proteins in either cells or isolated nuclei. Among these phosphoproteins, we identified the Vav adaptor in whole cells as well as in the inner nuclear compartment, where the increase in its tyrosine phosphorylation level was more conspicuous. We also demonstrated the differentiation-dependent association of nuclear phosphorylated Vav to phospholipase C-gamma1 and to the p85 regulatory subunit of phosphoinositide 3-kinase. The role of the Vav/phospholipase C-gamma1/phosphoinositide 3-kinase phosphoprotein complexes in the nuclei of HL-60 induced to differentiate along the granulocytic lineage is discussed
HIV-1 TAT PROTEIN SUPPRESSES THE NERVE GROWTH FACTOR (NGF)- MEDIATED DIFFERENTIATION OF PC12 RAT PHEOCHROMOCYTOMA CELL LINE
No full textIn order to evaluate the effect of the regulatory human immunodeficiency virus-type 1 (HIV-1) Tat protein on the process of neuronal differentiation, two tat-transfected and mock-transfected PC12 cell lines were cultured in the absence or presence of 100-1000 ng/ml of nerve growth factor (NGF). As expected, NGF was able to induce a clearcut morphological differentiation of mock-transfected PC12 into sympathetic-like neurons, also reducing the percentage of cells in S phase. On the other hand, NGF was unable to reduce the percentage of PC12-tat cells in S phase and/or to induce their neuronal differentiation. Only the addition in culture of 5 mu g/ml neutralizing anti-Tat antibody plus 1000 ng/ml NGF was effective in decreasing the percentage of PC12-tat in S phase and inducing partial signs of neuronal differentiation in serum-free cultures. The ability of Tat protein to suppress the neuronal differentiation pathway controlled by NGF further contribute to the definition of its role in tumor promotion during the course of HTV-1 disease
Inositide-modifying enzymes: a cooperative role in regulating nuclear morphology during differentiation of myeloid cells.
No full textDifferentiation and functional response of mature myeloid cells require cytoskeleton remodelling in a dynamic system that involves subcellular organization and regional signalling. Within the myeloid lineage, neutrophils constitute a cell type in which different cell compartments, and predominantly the nucleus, undergo distinctive large changes involving actin reorganization. In the context of the progressive elucidation of the nuclear structure and composition that has been achieved in the last two decades, it is now clear that the nucleus possesses an ordered and dynamic skeletal structure which shares many properties with the cytoskeleton, and the full set of substrates and enzymes that participate in the inositol lipid metabolism. Consolidated evidence indicate that the changes in cytoskeleton assembly are regulated also by phosphoinositides in a way dependent on their local concentration and availability. Indeed, enzymes able to affect the amount and phosphorylation of inositol lipids can play fundamental roles in determining the architectural transitions of the cell. The expression pattern and the changes of activity of PLC and PI 3-K in the nucleus during differentiation of tumoral myeloid precursors suggest that these enzymes play a crucial role in modifying the intranuclear pool of phosphoinositides, which in turn induce the changes in nucleoskeleton associated to granulocytic maturation. It can be speculated that defective control of nucleoskeleton assembly is one of the causes of dysregulated cell maturation or differentiative block in the course of myeloid leukemias. Inositide modifying enzymes can thus be regarded as potential targets for molecularly designed therapeutic intervention on hematological malignancies
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