scholarly journals Upregulation of Immunoregulatory Src Homology 2 Molecule Containing Inositol Phosphatase and Mononuclear Cell Hyporesponsiveness in Oral Mucosa during Chronic Periodontitis

2006 ◽  
Vol 74 (2) ◽  
pp. 1431-1435 ◽  
Author(s):  
Manoj Muthukuru ◽  
Christopher W. Cutler
Keyword(s):  
Oral Mucosa ◽  
Chronic Periodontitis ◽  
Mononuclear Cells ◽  
Endotoxin Tolerance ◽  
Negative Regulator ◽  
Inositol Phosphatase ◽  
Src Homology 2 ◽  
Tlr4 Mrna ◽  
Src Homology

ABSTRACT Our group and others have shown in vitro that repeated exposure of human mononuclear cells (MNC) to lipopolysaccharide can induce endotoxin tolerance, evidenced by downregulation of TLR2 and TLR4 mRNA and surface protein; moreover, the ability of the MNC to secrete inflammatory cytokines is reduced. In situ studies performed on diseased and healthy gingiva suggest that a similar pattern of endotoxin tolerance occurs in human oral mucosa with chronic periodontitis (CP). We hypothesized that this represents a fundamental immunoregulatory mechanism to restore immune homeostasis and protect the host from further tissue damage. In the current study, we extend these published studies by providing evidence that Src homology 2 containing inositol phosphatase, an inhibitor of NF-κB activation and a negative regulator of the immune response, is upregulated in the oral mucosa during CP compared to its level during gingival health. We have also isolated MNC from patients with CP and those with healthy gingiva and show that MNC from CP subjects have a reduced capacity to upregulate TLR2, TLR4, and interleukin-1β in response to endotoxin. Thus, we provide more definitive evidence for a basic mechanism of immunoregulation in the oral mucosa.

scholarly journals Oral Mucosal Endotoxin Tolerance Induction in Chronic Periodontitis

2005 ◽  
Vol 73 (2) ◽  
pp. 687-694 ◽  
Author(s):  
Manoj Muthukuru ◽  
Ravi Jotwani ◽  
Christopher W. Cutler
Keyword(s):  
Immune Response ◽  
Oral Mucosa ◽  
Chronic Periodontitis ◽  
Intracellular Signaling ◽  
Inflammatory Responses ◽  
Endotoxin Tolerance ◽  
Necrosis Factor Alpha ◽  
Initial Stimulus ◽  
Tlr4 Mrna ◽  
Tnf Α

ABSTRACT The oral mucosa is exposed to a high density and diversity of gram-positive and gram-negative bacteria, but very little is known about how immune homeostasis is maintained in this environment, particularly in the inflammatory disease chronic periodontitis (CP). The cells of the innate immune response recognize bacterial structures via the Toll-like receptors (TLR). This activates intracellular signaling and transcription of proteins essential for the induction of an adaptive immune response; however, if unregulated, it can lead to destructive inflammatory responses. Using single-immunoenzyme labeling, we show that the human oral mucosa (gingiva) is infiltrated by large numbers of TLR2+ and TLR4+ cells and that their numbers increase significantly in CP, relative to health (P < 0.05, Student's t test). We also show that the numbers of TLR2+ but not TLR4+ cells increase linearly with inflammation (r 2 = 0.33, P < 0.05). Double-immunofluorescence analysis confirms that TLR2 is coexpressed by monocytes (MC)/macrophages (mφ) in situ. Further analysis of gingival tissues by quantitative real-time PCR, however, indicates that despite a threefold increase in the expression of interleukin-1β (IL-1β) mRNA during CP, there is significant (30-fold) downregulation of TLR2 mRNA (P < 0.05, Student's t test). Also showing similar trends are the levels of TLR4 (ninefold reduction), TLR5 (twofold reduction), and MD-2 (sevenfold reduction) mRNA in CP patients compared to healthy persons, while the level of CD14 was unchanged. In vitro studies with human MC indicate that MC respond to an initial stimulus of lipopolysaccharide (LPS) from Porphyromonas gingivalis (PgLPS) or Escherichia coli (EcLPS) by upregulation of TLR2 and TLR4 mRNA and protein; moreover, IL-1β mRNA is induced and tumor necrosis factor alpha (TNF-α), IL-10, IL-6, and IL-8 proteins are secreted. However, restimulation of MC with either PgLPS or EcLPS downregulates TLR2 and TLR4 mRNA and protein and IL-1β mRNA and induces a ca. 10-fold reduction in TNF-α secretion, suggesting the induction of endotoxin tolerance by either LPS. Less susceptible to tolerance than TNF-α were IL-6, IL-10, and IL-8. These studies suggest that certain components of the innate oral mucosal immune response, most notably TLRs and inflammatory cytokines, may become tolerized during sustained exposure to bacterial structures such as LPS and that this may be one mechanism used in the oral mucosa to attempt to regulate local immune responses.

scholarly journals IL-6 blocks a discrete early step in lymphopoiesis

Blood ◽  
2005 ◽  
Vol 106 (3) ◽  
pp. 879-885 ◽  
Author(s):  
Kazuhiko Maeda ◽  
Yoshihiro Baba ◽  
Yoshinori Nagai ◽  
Kozo Miyazaki ◽  
Alexander Malykhin ◽  
...  
Keyword(s):  
Target Cells ◽  
Hematopoietic Progenitors ◽  
Early Step ◽  
Hematopoietic Stem ◽  
Lymphoid Lineage ◽  
Src Homology 2 ◽  
Multipotent Progenitors ◽  
Src Homology ◽  
Src Homology 2 Domain

Abstract Animals lacking Src homology 2 domain-containing inositol 5-phosphatase (SHIP) display a reduction in lymphopoiesis and a corresponding enhancement of myelopoiesis. These effects are mediated at least in part by elevated levels of interleukin 6 (IL-6). Here, we show the lymphopoiesis block in SHIP–/– mice is due to suppression of the lymphoid lineage choice by uncommitted progenitors. The suppression can be reproduced in vitro with recombinant IL-6, and IL-6 acts directly on hematopoietic progenitors. The block is partially overcome in SHIP–/– IL-6–/– double-deficient animals. IL-6 does not suppress but actually enhances proliferation of lymphoid-committed progenitors, indicating the IL-6 target cells are hematopoietic stem cells or multipotent progenitors. The findings suggest a mechanism for the lymphopenia that accompanies proinflammatory diseases.

scholarly journals Synthesis and in Vitro Evaluation of a Peptidomimetic Inhibitor Targeting the Src Homology 2 (SH2) Domain of STAT6

2013 ◽  
Vol 5 (1) ◽  
pp. 69-72 ◽  
Author(s):  
Pietro Morlacchi ◽  
Pijus K. Mandal ◽  
John S. McMurray
Keyword(s):  
Sh2 Domain ◽  
In Vitro Evaluation ◽  
Src Homology 2 ◽  
Src Homology

scholarly journals Src Homology 2 (SH2)-Containing 5′-Inositol Phosphatase Localizes to Podosomes, and the SH2 Domain Is Implicated in the Attenuation of Bone Resorption in Osteoclasts

Endocrinology ◽  
2006 ◽  
Vol 147 (7) ◽  
pp. 3307-3317 ◽  
Author(s):  
Keiichiro Yogo ◽  
Megumi Mizutamari ◽  
Kazuta Mishima ◽  
Hiromi Takenouchi ◽  
Norihiro Ishida-Kitagawa ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Nuclear Factor Κb ◽  
Sh2 Domain ◽  
Terminal Region ◽  
Spectrometric Analysis ◽  
Inositol Phosphatase ◽  
Amino Terminal ◽  
Novel Proteins ◽  
Src Homology 2 ◽  
Src Homology

c-Src plays an important role in bone resorption by osteoclasts. Here, we show using wild-type and ship−/− osteoclasts that Src homology 2 (SH2)-containing 5′-inositol phosphatase (SHIP) appeared to negatively regulate bone resorption activated by c-Src. SHIP was found to localize to podosomes under the influence of c-Src, and the presence of either the amino-terminal region comprising the SH2 domain or the carboxyl-terminal region was sufficient for its localization. Although SHIP lacking a functional SH2 domain was still found in podosomes, it could not rescue the hyper-bone resorbing activity and hypersensitivity to receptor activator of nuclear factor-κB ligand in ship−/− osteoclasts, suggesting that the localization of SHIP to podosomes per se was not sufficient and the SH2 domain was indispensable for its function. Cas and c-Cbl, known to function in podosomes of osteoclasts, were identified as novel proteins binding to the SHIP SH2 domain by mass spectrometric analysis, and this interaction appeared to be dependent on the Src kinase activity. These results demonstrate that c-Src enhances the translocation of SHIP to podosomes and regulates its function there through the SH2 domain, leading to an attenuation of bone resorption.

scholarly journals Chronic oral administration of P. gingivalis induces microglial activation and degeneration of dopaminergic neurons possibly through increase in gut permeability and peripheral IL-17A in LRRK2 R1441G mice

2020 ◽  
Author(s):  
Yu-kun Feng ◽  
Yan-Wen Peng ◽  
Qiong-Li Wu ◽  
Feng-Yin Liang ◽  
Hua-Jing You ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Chronic Periodontitis ◽  
Dopaminergic Neurons ◽  
Microglial Activation ◽  
Mononuclear Cells ◽  
Late Onset ◽  
Interleukin 1 ◽  
Peripheral Inflammation ◽  
Peripheral Blood Mononuclear

Abstract Background The R1441G mutation in the leucine-rich repeat kinase 2 (LRRK2) gene results in late-onset Parkinson’s disease (PD). Peripheral inflammation and gut microbiota are closely associated with the pathogenesis of PD. Chronic periodontitis is a common type of peripheral inflammation, which is associated with PD. Porphyromonas gingivalis (Pg), the most common bacterium causing chronic periodontitis, can cause alteration of gut microbiota. It is not known whether Pg-induced dysbiosis plays a role in the pathophysiology of PD. Methods In this study, live Pg were orally administrated to animals, three times a week for one month. Pg-derived lipopolysaccharide (LPS) was used to stimulate peripheral blood mononuclear cells in vitro. The effects of oral Pg administration on the gut and brain were evaluated through behaviors, morphology, and cytokine expression. Results Dopaminergic neurons in the substantia nigra were reduced and activated microglial cells were increased in R1441G mice given oral Pg. In addition, an increase in mRNA expression of tumor necrosis factor (TNF-α) and interleukin-1 β (IL-1β) as well as protein level of α-synuclein together with a decrease in zonula occludens-1 (Zo-1) were detected in the colon in Pg-treated R1441G mice. Furthermore, serum interleukin-17A (IL-17A) and brain IL-17 receptor A (IL-17RA) were increased in Pg-treated R1441G mice. Conclusions These findings suggest that LRRK2 causes gut leakage and further mediates peripheral IL-17A response in Pg-treated animals. We, thus, put forward the hypothesis that IL-17A in the serum may result in activation of the IL-17A-IL-17RA axis that aggravates dysfunction of dopaminergic neurons and provokes microglial activation in LRRK2 R1441G mice.

Triazolopyrimidinium salts: discovery of a new class of agents for cancer therapy

2020 ◽  
Vol 12 (5) ◽  
pp. 387-402
Author(s):  
Mariateresa Badolato ◽  
Fabrizio Manetti ◽  
Antonio Garofalo ◽  
Francesca Aiello
Keyword(s):  
Anticancer Agents ◽  
Docking Studies ◽  
In Vitro Models ◽  
Sh2 Domain ◽  
Activity Profile ◽  
Cancer Cell Growth ◽  
New Class ◽  
Src Homology 2 ◽  
Src Homology

Aim: The [1,2,4]triazolo[1,5- a]pyrimidine core is highly privileged in medicinal chemistry due to its versatile pharmacological activity profile. Recently, the search for novel anticancer agents has focused on [1,2,4]triazolo[1,5- a]pyrimidine derivatives. Results: Our hit functionalization has led to the discovery of new [1,2,4]triazolo[1,5- a]pyrimidinium salts with potential anticancer activity. Among a small library of molecules, compound 9 significantly inhibits cancer cell growth in a panel of in vitro models. Molecular docking studies and preliminary binding assay have displayed that 9 could directly bind the Src homology 2 (SH2) domain of STAT3 protein. Conclusion: Compound 9 is a novel promising lead compound that motivates additional evaluation of [1,2,4]triazolo[1,5- a]pyrimidinium salts as novel potential chemotherapeutics.

scholarly journals Cloning of a novel, ubiquitously expressed human phosphatidylinositol 3-kinase and identification of its binding site on p85.

1993 ◽  
Vol 13 (12) ◽  
pp. 7677-7688 ◽  
Author(s):  
P Hu ◽  
A Mondino ◽  
E Y Skolnik ◽  
J Schlessinger
Keyword(s):  
Cell Cycle Progression ◽  
Phosphatidylinositol 3 Kinase ◽  
Intact Cells ◽  
Src Homology 2 ◽  
Genes Encoding ◽  
Src Homology ◽  
Acid Domain ◽  
Vacuolar Protein ◽  
Phosphatidylinositol 3

Phosphatidylinositol 3-kinase (PI 3-kinase) has been implicated as a participant in signaling pathways regulating cell growth by virtue of its activation in response to various mitogenic stimuli. Here we describe the cloning of a novel and ubiquitously expressed human PI 3-kinase. The 4.8-kb cDNA encodes a putative translation product of 1,070 amino acids which is 42% identical to bovine PI 3-kinase and 28% identical to Vps34, a Saccharomyces cerevisiae PI 3-kinase involved in vacuolar protein sorting. Human PI 3-kinase is also similar to Tor2, a yeast protein required for cell cycle progression. Northern (RNA) analysis demonstrated expression of human PI 3-kinase in all tissues and cell lines tested. Protein synthesized from an epitope-tagged cDNA had intrinsic PI 3-kinase activity and associated with the adaptor 85-kDa subunit of PI 3-kinase (p85) in intact cells, as did endogenous human PI 3-kinase. Coprecipitation assays showed that a 187-amino-acid domain between the two src homology 2 domains of p85 mediates interaction with PI 3-kinase in vitro and in intact cells. These results demonstrate the existence of different PI 3-kinase isoforms and define a family of genes encoding distinct PI 3-kinase catalytic subunits that can associate with p85.

scholarly journals A Dual Role for Src Homology 2 Domain–Containing Inositol-5-Phosphatase (Ship) in Immunity

2000 ◽  
Vol 191 (5) ◽  
pp. 781-794 ◽  
Author(s):  
Cheryl D. Helgason ◽  
Christian P. Kalberer ◽  
Jacqueline E. Damen ◽  
Suzanne M. Chappel ◽  
Nicolas Pineault ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Development ◽  
B Cell Development ◽  
Lymphoid Development ◽  
Src Homology 2 ◽  
Src Homology ◽  
Src Homology 2 Domain ◽  
B Lymphoid

In this report, we demonstrate that the Src homology 2 domain–containing inositol-5-phosphatase (SHIP) plays a critical role in regulating both B cell development and responsiveness to antigen stimulation. SHIP−/− mice exhibit a transplantable alteration in B lymphoid development that results in reduced numbers of precursor B (fraction C) and immature B cells in the bone marrow. In vitro, purified SHIP−/− B cells exhibit enhanced proliferation in response to B cell receptor stimulation in both the presence and absence of Fcγ receptor IIB coligation. This enhancement is associated with increased phosphorylation of both mitogen-activated protein kinase and Akt, as well as with increased survival and cell cycling. SHIP−/− mice manifest elevated serum immunoglobulin (Ig) levels and an exaggerated IgG response to the T cell–independent type 2 antigen trinitrophenyl Ficoll. However, only altered B cell development was apparent upon transplantation into nonobese diabetic–severe combined immunodeficient (NOD/SCID) mice. The in vitro hyperresponsiveness, together with the in vivo findings, suggests that SHIP regulates B lymphoid development and antigen responsiveness by both intrinsic and extrinsic mechanisms.

scholarly journals Leishmania EF-1α Activates the Src Homology 2 Domain Containing Tyrosine Phosphatase SHP-1 Leading to Macrophage Deactivation

2002 ◽  
Vol 277 (51) ◽  
pp. 50190-50197 ◽  
Author(s):  
Devki Nandan ◽  
Taolin Yi ◽  
Martin Lopez ◽  
Crystal Lai ◽  
Neil E. Reiner
Keyword(s):  
Leishmania Donovani ◽  
Tyrosine Phosphatase ◽  
Elongation Factor ◽  
Host Protein ◽  
Src Homology 2 ◽  
Infected Cells ◽  
Src Homology ◽  
Src Homology 2 Domain

The human leishmaniasis are persistent infections of macrophages caused by protozoa of the genusLeishmania.The chronic nature of these infections is in part related to induction of macrophage deactivation, linked to activation of the Src homology 2 domain containing tyrosine phosphatase-1 (SHP-1) in infected cells. To investigate the mechanism of SHP-1 activation, lysates ofLeishmania donovanipromastigotes were subjected to SHP-1 affinity chromatography and proteins bound to the matrix were sequenced by mass spectrometry. This resulted in the identification ofLeishmaniaelongation factor-1α (EF-1α) as a SHP-1-binding protein. PurifiedLeishmaniaEF-1α, but not host cell EF-1α, bound directly to SHP-1in vitroleading to its activation. Three independent lines of evidence indicated thatLeishmaniaEF-1α may be exported from the phagosome thereby enabling targeting of host SHP-1. First, cytosolic fractions prepared from macrophages infected with [35S]methionine-labeled organisms containedLeishmaniaEF-1α. Second, confocal, fluorescence microscopy usingLeishmania-specific antisera detectedLeishmaniaEF-1α in the cytosol of infected cells. Third, co-immunoprecipitation showed thatLeishmaniaEF-1α was associated with SHP-1in vivoin infected cells. Finally, introduction of purifiedLeishmaniaEF-1α, but not the corresponding host protein into macrophages activated SHP-1 and blocked the induction of inducible nitric-oxide synthase expression in response to interferon-γ. Thus,LeishmaniaEF-1α is identified as a novel SHP-1-binding and activating protein that recapitulates the deactivated phenotype of infected macrophages.

scholarly journals Differential Regulation of B Cell Development, Activation, and Death by the Src Homology 2 Domain–Containing 5′ Inositol Phosphatase (Ship)

2000 ◽  
Vol 191 (9) ◽  
pp. 1545-1554 ◽  
Author(s):  
Anne Brauweiler ◽  
Idan Tamir ◽  
Joseph Dal Porto ◽  
Robert J. Benschop ◽  
Cheryl D. Helgason ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Cell Development ◽  
B Cell Development ◽  
Inositol Phosphatase ◽  
Src Homology 2 ◽  
Src Homology ◽  
Src Homology 2 Domain ◽  
Deficient Mice

Although the Src homology 2 domain–containing 5′ inositol phosphatase (SHIP) is a well-known mediator of inhibitory signals after B cell antigen receptor (BCR) coaggregation with the low affinity Fc receptor, it is not known whether SHIP functions to inhibit signals after stimulation through the BCR alone. Here, we show using gene-ablated mice that SHIP is a crucial regulator of BCR-mediated signaling, B cell activation, and B cell development. We demonstrate a critical role for SHIP in termination of phosphatidylinositol 3,4,5-triphosphate (PI[3,4,5]P3) signals that follow BCR aggregation. Consistent with enhanced PI(3,4,5)P3 signaling, we find that splenic B cells from SHIP-deficient mice display enhanced sensitivity to BCR-mediated induction of the activation markers CD86 and CD69. We further demonstrate that SHIP regulates the rate of B cell development in the bone marrow and spleen, as B cell precursors from SHIP-deficient mice progress more rapidly through the immature and transitional developmental stages. Finally, we observe that SHIP-deficient B cells have increased resistance to BCR-mediated cell death. These results demonstrate a central role for SHIP in regulation of BCR signaling and B cell biology, from signal driven development in the bone marrow and spleen, to activation and death in the periphery.

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