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Query: EC:2.7.10.2 (
focal adhesion kinase
)
44,029
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Severe impairment in the functions of immune-competent cells has been observed following trauma and hemorrhage. Inappropriate release of cytokines during trauma and hemorrhagic shock disrupt T lymphocyte functions and enable cells to activate genes whose products are detrimental for maintaining a much-needed humoral and cell-mediated immunity. The intracellular events for gene activation are mediated by cytoplasmic transcription factors present as nascent (signal transducer and activator of transcription 1 (STAT 1)) or as a complex (nuclear factor kappaB (NF-kappaB)). Receptor-initiated phosphorylation activates these transcription factors prior to their nuclear translocation and binding to cognate DNA sequences. Because T cell functions are critical to efficient functioning of the immune system, we investigated whether expression of transcription factors, STAT1 and NF-kappaB, is perturbed in splenic T cells following trauma and hemorrhage. To study this, enriched T cells harvested from spleens (pooled from three or four mice per group) of sham, trauma (consisting of midline laparotomy), sham+trauma, hemorrhage (blood pressure maintained at approximately 30 mmHg for 90 min followed by adequate fluid resuscitation), and trauma+hemorrhage groups at 16-18 h after surgical procedure were probed for signal expressions in the presence and absence of
interferon-gamma
using electrophoretic mobility shift and Western immunoblot assay procedures. Hemorrhage with or without trauma induced activation of
Janus kinase 1
, STAT1, and NF-kappaB in T cells. Stimulation of T cells with
interferon-gamma
led to activation of all these signals in all groups including experimental controls. STAT1 activation was accompanied by
Janus kinase 1
phosphorylation, whereas NF-kappaB activation was mediated by phosphorylation and rapid degradation of IkappaBalpha. These studies demonstrate that hemorrhagic shock, with or without laparotomy, is sufficient to induce activation of transcription factors in splenic T cells. Thus, attempts to prevent the activation of transcription factors following hemorrhage by pharmacologic means might be helpful for maintaining cell-mediated immunity under these conditions.
...
PMID:Trauma-hemorrhage activates signal transduction pathways in mouse splenic T cells. 964 97
A large number of continuous human leukemia cell lines have been established over the last three decades. Clearly, leukemia cell lines have become important research tools. Here, we have summarized the immunological, molecular and standard cytogenetic features of a panel of well characterized B cell precursor (BCP)-leukemia cell lines which were derived from patients with acute lymphoblastic/undifferentiated leukemia (ALL/AUL) or chronic myeloid leukemia (CML) in blast crisis. Following the recently proposed immunological EGIL classification, we assigned our panel of 27 BCP-cell lines to one of the following categories: B-I pro-B cell line; B-II common-B cell line; and B-III pre-B cell line. All cell lines express general B-lineage associated surface markers (HLA-DR, CD22, CD79a) being negative for surface immunoglobulin (Ig); the differences between the subgroups reside in expression of CD10 and cytoplasmic Ig. Several BCP-cell lines show the myelomonocytic cell-associated markers CD13 and/or CD33. These immunologically 'biphenotypic' BCP-cell lines are generally TdT+ CD10+ CD13+ CD19+ CD22+ CD34+ and carry the Philadelphia (Ph) translocation. The BCP-cell lines display surface receptors for
interferon-gamma
(CD119), interleukin-7 (CD127) and FLT-3 ligand (CD135). All BCP-cell lines examined have complex numerical and structural chromosomal alterations including translocations commonly seen in BCP-ALL such as t(4;11), t(9;22), t(11;19), t(12;21), and t(17;19) involving the fusion genes MLL-AF4, BCR-
ABL
, ENL-MLL, TEL/ETV6-AML1 and E2A-HLF, respectively. Besides the expected rearrangement of the Ig heavy chain receptor gene, several cell lines also have rearrangements of the T cell receptor genes beta, gamma or delta. While some BCP-cell lines express (aberrantly) myeloperoxidase at the mRNA level, most lines are negative in the immunological or cytochemical staining. Several large series documented the difficulty in establishing such BCP cell lines with success rates in the range of 10-20% (on average 15%). Still, since the establishment of the first bonafide BCP-cell line in 1974 (cell line REH), some 150 cell lines have been established of which, however, only a small percentage have been sufficiently well characterized and described. A higher success rate for immortalizing any given leukemia cell might depend on a closer emulation of the physiological in vivo microenvironment. The possibility to grow in vitro leukemia cells at will would represent ideal experimental systems permitting basic research and patient-specific investigations. In summary, the use of well-characterized BCP-cell lines provide unprecedented opportunities for studying a multitude of biological aspects related to normal and neoplastic B-lymphocytes.
...
PMID:Establishment and characterization of human B cell precursor-leukemia cell lines. 968 Jan 6
We recently identified SH2-Bbeta as a
JAK2
-binding protein and substrate involved in the signaling of receptors for growth hormone and
interferon-gamma
. In this work, we report that SH2-Bbeta also functions as a signaling molecule for platelet-derived growth factor (PDGF). SH2-Bbeta fused to glutathione S-transferase (GST) bound PDGF receptor (PDGFR) from PDGF-treated but not control cells. GST fusion protein containing only the SH2 domain of SH2-Bbeta also bound PDGFR from PDGF-treated cells. An Arg to Glu mutation within the FLVRQS motif in the SH2 domain of SH2-Bbeta inhibited GST-SH2-Bbeta binding to tyrosyl-phosphorylated PDGFR. The N-terminal truncated SH2-Bbeta containing the entire SH2 domain interacted directly with tyrosyl-phosphorylated PDGFR from PDGF-treated cells but not unphosphorylated PDGFR from control cells in a Far Western assay. These results suggest that the SH2 domain of SH2-Bbeta is necessary and sufficient to mediate the interaction between SH2-Bbeta and PDGFR. PDGF stimulated coimmunoprecipitation of endogenous SH2-Bbeta with endogenous PDGFR in both 3T3-F442A and NIH3T3 cells. PDGF stimulated the rapid and transient phosphorylation of SH2-Bbeta on tyrosines and most likely on serines and/or threonines. Similarly, epidermal growth factor stimulated the phosphorylation of SH2-Bbeta; however, phosphorylation appears to be predominantly on serines and/or threonines. In response to PDGF, SH2-Bbeta associated with multiple tyrosyl-phosphorylated proteins, at least one of which (designated p84) does not bind to PDGFR. Taken together, these data strongly argue that, in response to PDGF, SH2-Bbeta directly interacts with PDGFR and is phosphorylated on tyrosine and most likely on serines and/or threonines, and acts as a signaling protein for PDGFR.
...
PMID:Platelet-derived growth factor (PDGF) stimulates the association of SH2-Bbeta with PDGF receptor and phosphorylation of SH2-Bbeta. 969 82
It has been proposed elsewhere that thyrocyte (
TEC
) class I expression plays a central role in the pathogenesis of autoimmune thyroid disease (AITD). We have studied thyroid xenografts from patients with Graves' disease (GD) and normal (paranodular) (N) tissues in nude and severe combined immunodeficient (SCID) mice.
TEC
class I and II expression are markedly increased in GD, as compared with N thyroids. When these tissues are transplanted to nude mice in which the immune environment is deleted from the thyroid grafts,
TEC
class I and class II expression decline to low levels;
interferon-gamma
(
IFN-gamma
) but not interferon-alpha (IFN-alpha) will then upregulate
TEC
class I and class II expression in these N and GD nude xenografts. In SCID mouse xenografts, GD tissue shows higher
TEC
class I and II expression compared with N. In these SCID mice, both IFN-alpha and
IFN-gamma
will stimulate
TEC
class I and II expression further in both GD and N. However, only IFN-alpha increases thyroid antibody (TAb) production from GD SCID grafts, whereas
IFN-gamma
causes a rise in GD
TEC
class I and II expression, but no significant increase in TAb. Moreover, in N SCID grafts, despite a rise in
TEC
class I and II expression induced by both IFNs, no TAb could be detected. Because an immune environment is necessary for
TEC
class I and II upregulated expression, we conclude that such upregulation is a secondary phenomenon. Because there was dissociation between the stimulation of
TEC
class I and II expression versus the production of TAb, then at least under these experimental conditions, there is no support for a role for
TEC
class I and class II upregulation in the pathogenesis of AITD.
...
PMID:Thyrocyte class I and class II upregulation is a secondary phenomenon and does not contribute to the pathogenesis of autoimmune thyroid disease. 977 45
GH and its related peptide PRL are known to stimulate proliferation and insulin biosynthesis in pancreatic beta-cells, and assumed to be involved in their functional maturation. We investigated signal transduction of GH and PRL in insulin-secreting cells using the differentiated rat insulinoma cell line, INS-1. In these cells, both hormones stimulated proliferation and DNA synthesis, increased viability, cellular metabolism and insulin content. GH induced cytosolic Ca2+ ([Ca2+]i) rises, which appear to be due to Ca2+-influx through voltage-gated Ca2+-channels. GH also promoted tyrosine phosphorylation of several proteins in INS-1 cells, one of which was identified as
JAK2
tyrosine kinase. Moreover, GH caused changes in DNA binding of nuclear proteins to some
interferon-gamma
-activated sites. Verapamil inhibited neither DNA synthesis nor
JAK2
phosphorylation stimulated by GH, whereas a tyrosine kinase inhibitor, lavendustin A, blocked the mitogenic effect. Involvement of cAMP is also suggested because Rp-cAMPS, a competitive inhibitor of protein kinase A, abolished both [Ca2+]i rises and DNA synthesis stimulated by GH. The effects of GH and PRL on [Ca2+]i,
JAK2
phosphorylation and DNA binding of the STATs were virtually identical in INS-1 cells. Since both hormones failed to activate MAP kinase in these cells, it is strongly suggested that activation of the JAK-STAT pathway is the major signalling event for the mitogenic effects of GH and PRL in beta-cells. It remains to be clarified whether the [Ca2+]i rise mediates other effects of these hormones.
...
PMID:GH signalling in pancreatic beta-cells. 979 Feb 27
Interleukin-12 (IL-12) is a cytokine that plays a central role in the control of cell-mediated immunity. We have previously shown that transforming growth factor-beta1 (TGF-beta) inhibitory effects on human primary allogeneic cytotoxicity and proliferative responses interfere with IL-12 pathway. The present study was undertaken to further elucidate the biochemical basis of the functional interaction between these two cytokines and to define the site of TGF-beta action on the signaling pathway activated by IL-12. Our data indicate that TGF-beta induced an inhibition of
interferon-gamma
(
IFN-gamma
) production without affecting the IL-12Rbeta1 and IL-12Rbeta2 subunits mRNA expression by activated T cells. We further show that TGF-beta has a significant inhibitory effect on the early signal transduction events following interaction of IL-12 with its receptor on activated T cells, resulting in the inhibition of both
JAK2
and Tyk2 phosphorylation. In addition, TGF-beta was found to significantly inhibit IL-12-induced phosphorylation of the STAT4 transcription factor. Electrophoretic mobility shift assay indicated that TGF-beta induced a decrease in IL-12-induced STAT4 DNA binding activity in T lymphocytes. This study suggests that TGF-beta influences IL-12 responsiveness at least in part by inhibiting early signaling events essential to gene induction in IL-12-activated T cells.
...
PMID:Downregulation of interleukin-12 (IL-12) responsiveness in human T cells by transforming growth factor-beta: relationship with IL-12 signaling. 1002 70
Binding of
interferon-gamma
(
IFN-gamma
) to its heterodimeric receptor induces activation of the tyrosine kinases
JAK1
and
JAK2
followed by tyrosine phosphorylation of STAT1alpha. Selective activation of STAT1alpha at the
IFN-gamma
receptor is achieved by specific interaction between a cytosolic tyrosine motif including Y440 in the
IFN-gamma
receptor alpha-chain and the SH2 domain of STAT1alpha. We demonstrate that, in addition to STAT1alpha, STAT3 is also activated by
IFN-gamma
in human neutrophils. The activation of STAT3 was not found in human eosinophils, monocytes, and HL-60 cells, although the STAT3 protein was expressed in these cells. The cell type-specific activation of STAT3 by
IFN-gamma
was also observed in neutrophils that are differentiated in vitro from human CD34+ hematopoietic stem cells. These results indicate that a single cytokine receptor can activate different STAT family members in a cell-specific manner, which might result in cell-specific gene transcription.
...
PMID:Lineage-specific activation of STAT3 by interferon-gamma in human neutrophils. 1008 May 44
The contribution of nuclear factor-kappaB (NF-kappaB) and
interferon-gamma
(
IFN-gamma
) signaling to nitric oxide generation is not completely understood. The effect of NF-kappaB release and its inhibition on nitrite production and the involvement of
Janus kinase 2
(
JAK2
) in inducible nitric oxide synthase (iNOS) induction were investigated. The following assays were performed. (1) Nitrite produced by rat mesangial cells in primary culture was measured in incubations with tumor necrosis factor-alpha (TNF-alpha) or lipopolysaccharide (LPS), with or without
IFN-gamma
. Cells were stimulated with TNF-alpha or LPS plus
IFN-gamma
in the presence of NF-kappaB inhibitors, herbimycin A (HerA), or the more specific
JAK2
inhibitor AG490. (2) Immunoblotting was performed against the p65 and p50 subunits of NF-kappaB and iNOS. (3) Electrophoretic mobility shift assays were performed against NF-kappaB in the presence of NF-kappaB inhibitors or AG490. (4) iNOS promoter activity was measured in the presence of AG490 or
JAK2
antisense oligonucleotides. TNF-alpha or LPS alone did not induce nitrite production, but with
IFN-gamma
these compounds did induce nitrite production. Pyrrolidine dithiocarbamate (PDTC), N-acetyl-L-cysteine, dexamethasone (Dex), HerA, and AG490 partially inhibited LPS/
IFN-gamma
- or TNF-alpha/
IFN-gamma
-induced nitrite production. p65 was inhibited by the three NF-kappaB inhibitors described above, whereas p50 was not. PDTC and Dex completely inhibited the p65/p50 heterodimer, but HerA and AG490 had little effect on p65/p50. AG490 and
JAK2
antisense oligonucleotides suppressed iNOS promoter activity. It can be concluded that (1) iNOS can be induced without active NF-kappaB; (2) Dex, acetylsalicylic acid, and PDTC inhibit only p65; and (3)
JAK2
is involved in iNOS induction, and the contribution of
JAK2
to nitrite production is greater than that of NF-kappaB.
...
PMID:Inducible nitric oxide synthase can be induced in the absence of active nuclear factor-kappaB in rat mesangial cells: involvement of the Janus kinase 2 signaling pathway. 1020 55
Previous studies by us and others have demonstrated the expression of acetylcholine receptors on epithelial cells in the thymus of myasthenia gravis (MG) and control subjects. In the present experiments, we used a reverse transcription-polymerase chain reaction (RT-PCR) to analyze the profile of the two major isoforms of the alpha chain of these receptors (AChRalpha), P3A- and P3A+, in thymus tissue obtained from MG and control subjects and a human thymic epithelial cell line (TEC9). In addition, using a semiquantitative RT-PCR, we compared the amounts of P3A- and P3A+ mRNA expressed in thymic tissue obtained from these two sources and determined if their expression in TEC9 is modulated by cytokines. We found that mRNAs encoding P3A- and P3A+ are expressed at approximately a 5:1 ratio in both MG and control thymus tissue. This contrasts with skeletal muscle where mRNAs encoding these isoforms are expressed equally. A pattern of preferential P3A- vs P3A+ mRNA expression was also observed in TEC9. We observed 2.8-fold greater expression of both isoforms in MG than in control thymus. Expression of both isoforms in TEC9 was enhanced significantly by treatment with
interferon-gamma
whereas IL-1alpha, IL-4, and IL-6 had no effect. Thus, there is differential regulation of AChRalpha variants in thymus and
TEC
relative to muscle and
interferon-gamma
represents a novel regulator of AChRalpha mRNA expression. MG thymus is distinguished by increased expression of both isoforms of this autoantigen, a finding that may reflect enhancement of transcription by local microenvironmental factors.
...
PMID:Acetylcholine receptor alpha subunit mRNA expression in human thymus: augmented expression in myasthenia gravis and upregulation by interferon-gamma. 1022 9
Tyrosine phosphorylation pathways are essential components of the process of macrophage activation and the resultant production of inflammatory mediators such as tumor necrosis factor (TNF) and nitric oxide (NO). Several lines of evidence suggest that members of the src family of protein tyrosine kinases play important roles in macrophage activation by gram-negative bacterial lipopolysaccharide (LPS) or the cytokine
interferon-gamma
(
IFN-gamma
), but targeted disruption of three members of the src family (hck, fgr, and lyn) in mice failed to demonstrate a requirement for these particular kinases in macrophage activation. We report that the pyrazolopyrimidine PP1, a src family-selective tyrosine kinase inhibitor, potently inhibits the production of TNF and inducible nitric oxide synthase (iNOS) in RAW 264.7 murine macrophages stimulated with LPS, rlFN-gamma, or LPS + rIFN-gamma. Furthermore, the tested concentrations of PP1 inhibit LPS- and rlFN-gamma-mediated tyrosine phosphorylation of the hck tyrosine kinase and its putative substrate, vav, but fail to block rlFN-gamma-mediated
JAK2
tyrosine phosphorylation. These findings provide additional support for a model of macrophage activation involving one or more src-related kinases. Selective inhibitors of this signaling pathway should be studied in animal models of sepsis.
...
PMID:The src family-selective tyrosine kinase inhibitor PP1 blocks LPS and IFN-gamma-mediated TNF and iNOS production in murine macrophages. 1056 9
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