P38 MAPK Activity in Myeloma Cells Regulates Osteoclast and Osteoblast Activity and Induces Bone Destruction in Vivo

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 566-566
Author(s):  
Jin He ◽  
Zhiqiang Liu ◽  
Yuhuan Zheng ◽  
Jianfei Qian ◽  
Haiyan Li ◽  
...  
Keyword(s):  
Bone Resorption ◽  
P38 Mapk ◽  
Conflicts Of Interest ◽  
Bone Destruction ◽  
Mapk Signaling ◽  
Bone Lesions ◽  
Array Analysis ◽  
Mapk Activity ◽  
The Impact

Abstract Abstract 566 Bone destruction is a hallmark of multiple myeloma (MM). More than 80% of MM patients have osteolysis, which is characterized by pathological fractures, severe bone pain, spinal cord compression, and hypercalcemia. These symptoms can severely compromise a patient's quality of life and performance status. It has been proposed that MM cells activate osteoclast (OC)-mediated bone resorption and inhibit osteoblast (OB)-mediated bone formation. However, the mechanism underlying the association of MM cells with development of bone lesions remains poorly elucidated. Our previous studies showed that p38 mitogen-activated protein kinase (MAPK), which is constitutively activated in MM cells, is a master regulator of MM-mediated bone destruction. Knocking down or inhibiting p38 MAPK activity in MM cells prevented MM-induced bone destruction in vivo. In the present study, we further investigated the mechanism of MM cell p38 MAPK-induced bone destruction. We hypothesized that p38 MAPK activity in MM cells can regulate OB and OC differentiation and activity by upregulating cytokine production by MM cells. In a cytokine array analysis, we examined the expression and secretion of MM-derived cytokines that regulate OB and OC differentiation. Our results showed for the first time that either knockdown or inhibition of p38 MAPK activity by p38 MAPK short hairpin RNAs or inhibitors significantly downregulated the production of dickkopf-1 (DKK-1) and monocyte chemotactic protein-1 (MCP-1) by MM cells. Real-time PCR and ELISA quantified and confirmed the array analysis results. To determine the role of p38 MAPK-upregulated DKK-1 and MCP-1 production in bone destruction, we administered treatment with neutralizing antibodies to SCID mice injected intravenously with ARP-1 or MM.1S cells. Our results showed that neutralization of DKK-1 and MCP-1 led to fewer bone lesions in these mice. Furthermore, we examined the impact of MM cell p38 MAPK activity on OB and/or OC differentiation. Our results showed that knockdown or inhibition of MM cell p38 MAPK significantly downregulated osteoclastogenesis but upregulated osteoblastogenesis in vitro and in vivo. Although DKK-1 is well known to inhibit OB differentiation, we found that DKK-1, together with MCP-1, promoted OC differentiation and bone resorption. Mechanistic studies further showed that MCP-1 upregulated RANK expression in OC precursors and that DKK-1 increased RANKL secretion from stromal cells and mature OBs, all of which led to activation of the NF-kB and MAPK signaling pathways in OCs. Thus, our study uncovered a novel mechanism by which p38 MAPK signaling in MM cells regulates osteoblastogenesis, osteoclastogenesis, and bone destruction in patients with this disease. These findings strongly suggest that disrupting and targeting MM cell p38 signaling are effective approaches to treating osteolytic bone lesions in MM patients. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Pantoprazole (PPZ) Inhibits RANKL-Induced Osteoclast Formation and Function In Vitro and Prevents Lipopolysaccharide- (LPS-) Induced Inflammatory Calvarial Bone Loss In Vivo

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yu-Xi Li ◽  
Fu-Chao Chen ◽  
Ting Liu ◽  
Zhao-Peng Cai ◽  
Keng Chen ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Matrix ◽  
Bone Destruction ◽  
Mapk Signaling ◽  
Marker Genes ◽  
Calvarial Bone ◽  
Hematopoietic Stem ◽  
Increased Risk

Bone remodeling is a process delicately balanced between osteoclastic bone resorption and osteoblastic bone formation. Osteoclasts (OCs) are multinucleated giant cells formed through the fusion of monocytic precursors of the hematopoietic stem cells lineage. OCs are the exclusive cells responsible for the resorption and degradation of the mineralized bone matrix. Pantoprazole (PPZ), a proton pump inhibitor (PPI), is commonly prescribed to reduce excess gastric acid production for conditions such as gastroesophageal reflux disease and peptic ulcer disease. Studies have found contradictory effects of PPI therapy on bone metabolism due to the lack of understanding of the exact underlying mechanism. In this study, we found that PPZ inhibits receptor activator of nuclear factor-κB (NF-κB) ligand- (RANKL-) induced osteoclastogenesis from bone marrow monocytic/macrophage (BMMs) precursors and the bone-resorbing activity of mature OCs. Correspondingly, the expression of OC marker genes was also attenuated. At the molecular level, PPZ treatment was associated with reduced activation of the ERK MAPK signaling pathways crucial to OC differentiation. Additionally, the in vivo administration of PPZ protected mice against lipopolysaccharide- (LPS-) induced inflammatory calvarial bone erosion, as a result of the reduced number and activity of OCs on the calvarial bone surface. Although PPI use is associated with increased risk of osteoporosis and bone fractures, our study provides evidence for the direct inhibitory effect of PPZ on OC formation and bone resorption in vitro and in vivo, suggesting a potential therapeutic use of PPZ in the treatment of osteolytic disease with localized bone destruction.

SB431542, a TGF-Beta Receptor Kinase Inhibitor, Restores Bone Formation Which Ameliorates Myeloma-Induced Microenvironment.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3479-3479 ◽  
Author(s):  
Kyoko Takeuchi ◽  
Masahiro Abe ◽  
Asuka Oda ◽  
Hiroe Amou ◽  
Masahiro Hiasa ◽  
...  
Keyword(s):  
Cell Growth ◽  
Bone Resorption ◽  
Bone Formation ◽  
Bone Destruction ◽  
Bone Lesions ◽  
Nodule Formation ◽  
Type I ◽  
Receptor Kinase ◽  
Tgf Beta ◽  
The Impact

Abstract Multiple myeloma (MM) cells stimulate bone resorption and concomitantly suppress bone formation, leading to devastating bone destruction. TGF-beta, a potent inhibitor for terminal osteoblasts (OB) maturation and mineralization, is abundantly produced and released from bone tissues through enhanced bone resorption, and activated by osteoclasts (OC)-derived acids and MMPs in MM bone lesions. In the present study we investigated the impact of TGF-beta inhibition on induction of bone formation in MM as well as the effects of matured OB on MM growth. TGF-beta completely suppressed BMP-2-induced mineralized nodule formation by OB cultured in osteogenic media supplemented with beta-glycerophosphate and vitamin C. SB431542, an inhibitor of TGF-beta type I receptor kinase, potently suppressed induction of Smad6 by TGF-beta, which inhibits BMP-2 signaling. SB431542 along with BMP-2 abolished such TGF-beta actions and enhanced mineralized nodule formation more than BMP-2 alone. Notably, addition of SB431542 antagonized the inhibitory effects of conditioned media from MM cell lines (RPMI8226 and U266) and bone marrow plasma from patients with MM, resulting in restoration of the BMP-induced mineralized nodule formation. Furthermore, MC3T3-E1 cells matured by BMP-2 enough to exhibit mineralized nodules suppressed the proliferation of 5TGM1 MM cells in sharp contrast to stromal cells as well as untreated or TGF-beta-treated undifferentiated MC3T3-E1 cells that promote MM cell growth and survival. Interestingly, 5TGM1 MM cell growth was also potently suppressed by MC3T3-E1 cells cultured with BMP-2 in the absence of beta-glycerophosphate to achieve OB maturation without formation of mineralized nodules, suggesting a responsible role for OB-derived non-mineralized factors associated with terminal differentiation of OB. In addition, the induction of OB maturation down-regulated the production by OB of IL-6 and up-regulated osteoprotegerin, an inhibitor for osteoclastogenesis. Taken together, blockade of TGF-beta actions release OB from the differentiational arrest in MM bone disease and thus can be a good therapeutic maneuver restoring bone formation as well as suppressing osteoclastogenesis to ameliorate bone destruction and at the same time suppressing MM expansion by disrupting the MM-induced microenvironment which can be called as MM niche.

scholarly journals α-Mangostin Inhibits LPS-Induced Bone Resorption by Restricting Osteoclastogenesis Via NF-κB and MAPK Signaling

2021 ◽  
Author(s):  
Wenkan Zhang ◽  
guangyao Jiang ◽  
xiaozhong zhou ◽  
leyi huang ◽  
jiahong meng ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Therapeutic Potential ◽  
Bone Destruction ◽  
Mapk Signaling ◽  
Osteoclast Formation ◽  
Receptor Activator ◽  
Cardioprotective Effects ◽  
And Function

Abstract Background: Excessive activation of osteoclasts is an important cause of imbalance in bone remodeling, which further leads to pathological bone destruction. This is a clear feature of many osteolytic diseases, such as rheumatoid arthritis, osteoporosis, and osteolysis around the prosthesis. Based on the fact that many natural compounds have therapeutic potential for treating these diseases by suppressing osteoclast formation and function, we proved that α-mangostin, a natural compound isolated from mango, might be a promising choice. α-mangostin was described had anti‐inflammatory, anticancer and cardioprotective effects. Methods: We evaluated the therapeutic effect of α-mangostin in the process of osteoclast formation and bone resorption. The receptor activator of NF-κB ligand (RANKL) induces the formation of osteoclasts in vitro, and the potential pathways of α-mangostin to inhibit the differentiation and function of osteoclasts were explored. A mouse model of LPS‐induced calvarial osteolysis was establish. Subsequently, micro-CT, histology, etc. were used to evaluate the effect of α-mangostin in preventing inflammatory osteolysis.Results: In our study, we found that α-mangostin could inhibit RANKL-induced osteoclastogenesis and reduced osteoclast‐related gene expression in vitro. Besides, F-actin ring immunofluorescence and resorption pit assay indicated that α-mangostin can also destroy the function of osteoclast. Furthermore, α-mangostin achieved these effects by disrupting the activation of NF-κB/MAPKs signaling pathways. In vivo, our data revealed that α-mangostin could protect mouse calvarial from osteolysis. Conclusions: Together, our study demonstrates that α-mangostin exhibit the ability of inhibiting steoclastogenesis both in vitro and in vivo, and may be a potential option for treating osteoclast‐related diseases.

Constitutive Activation of p38 MAPK in Myeloma Cells Contributes to Myeloma-Induced Osteolytic Bone Lesions.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 740-740
Author(s):  
Jing Yang ◽  
Yabing Cao ◽  
Yuhuan Zheng ◽  
Sungyoul Hong ◽  
Haiyan Li ◽  
...  
Keyword(s):  
Bone Resorption ◽  
P38 Mapk ◽  
Cell Lines ◽  
Scid Mice ◽  
Bone Lesions ◽  
Type I ◽  
Mapk Activation ◽  
Myeloma Cells ◽  
Constitutive Activation

Abstract Abstract 740 Bone destruction is common in osteolytic tumors such as multiple myeloma. Myeloma cells that reside in the bone cause osteolysis, which is characterized by severe bone pain, multiple fractures, and hypercalcemia in patients and thereby, compromises patient quality of life. While myeloma cells have been proposed to activate osteoclasts and/or inhibit osteoblasts leading to bone resorption, the mechanism underlying myeloma-induced osteolytic bone lesions is still poorly elucidated. As p38 mitogen-activated protein kinase (MAPK) is constitutively activated in myeloma, we hypothesized that p38 MAPK activation in myeloma cells might be responsible for myeloma-induced osteolytic bone lesions. Human myeloma cell lines ARP-1 and MM.1S caused bone lesions in SCID mice after intravenous injection. However, once p38 MAPK was knocked down by small hairpin RNAs (shRNAs) in these cell lines, myeloma was established but failed to cause bone lesions in SCID mice, whereas the wild-type or vector control myeloma cells established myeloma (with similar tumor burdens as myeloma cells with knocked-down p38 MAPK) and caused bone lesions in tibial bones, as measured by radiograph and peripheral quantitative m-computed tomography and further confirmed by histological examination. In vivo examination revealed that the number of bone surface-covering osteoclasts, osteoclast size, cellular nuclear numbers in per osteoclast, and levels of circulating collagen type I (bone resorption marker) and TRAP5b (active osteoclast marker) were all reduced in mice injected with myeloma cells with knocked-down p38 MAPK as compared with controls. Consistently, we found that tumor p38 MAPK had active effects on in vitro osteoclast differentiation and bone resorption, and inhibited osteoblast differentiation and function, suggesting that constitutive activation of p38 MAPK in myeloma cells induces osteoclastogenesis. By functional studies and protein array analysis, we showed that monocyte chemotactic protein-1 (MCP-1) and dickkopf-1 (DKK-1) are upregulated downstream of p38 MAPK activation in myeloma cells and are responsible for enhanced osteoclastogenesis. Our results showed that p38 MAPK activation in myeloma cells upregulate MCP-1 and DKK-1 expression and production, which are released into the microenvironment. MCP-1 enhanced RANK expression on osteoclast precursors and DKK-1 increased RANKL secretion from stromal cells, all of which led to activation of NF-kB and MAPK signaling pathways in osteoclasts. In vivo blockade of MCP-1 and DKK-1 by specific antibodies significantly abrogated tumor p38 MAPK-induced osteoclast activation and bone lesions in established myeloma-SCID mice. Thus, our results have elucidated a novel mechanism that p38 MAPK activity in myeloma cells contributes to myeloma-induced osteolytic bone lesions. This study indicates that disruption of tumor p38 MAPK may be a new therapeutic approach to treat osteolytic bone lesions in myeloma. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Hypoxia-induced CREB cooperates MMSET to modify chromatin and promote DKK1 expression in multiple myeloma

Oncogene ◽  
2021 ◽  
Author(s):  
Yinyin Xu ◽  
Jing Guo ◽  
Jing Liu ◽  
Ying Xie ◽  
Xin Li ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Combined Treatment ◽  
Hypoxia Inducible Factor ◽  
Bone Destruction ◽  
Bone Lesions ◽  
Myeloma Cells ◽  
Downstream Target ◽  
Dkk1 Expression

AbstractMyeloma cells produce excessive levels of dickkopf-1 (DKK1), which mediates the inhibition of Wnt signaling in osteoblasts, leading to multiple myeloma (MM) bone disease. Nevertheless, the precise mechanisms underlying DKK1 overexpression in myeloma remain incompletely understood. Herein, we provide evidence that hypoxia promotes DKK1 expression in myeloma cells. Under hypoxic conditions, p38 kinase phosphorylated cAMP-responsive element-binding protein (CREB) and drove its nuclear import to activate DKK1 transcription. In addition, high levels of DKK1 were associated with the presence of focal bone lesions in patients with t(4;14) MM, overexpressing the histone methyltransferase MMSET, which was identified as a downstream target gene of hypoxia-inducible factor (HIF)-1α. Furthermore, we found that CREB could recruit MMSET, leading to the stabilization of HIF-1α protein and the increased dimethylation of histone H3 at lysine 36 on the DKK1 promoter. Knockdown of CREB in myeloma cells alleviated the suppression of osteoblastogenesis by myeloma-secreted DKK1 in vitro. Combined treatment with a CREB inhibitor and the hypoxia-activated prodrug TH-302 (evofosfamide) significantly reduced MM-induced bone destruction in vivo. Taken together, our findings reveal that hypoxia and a cytogenetic abnormality regulate DKK1 expression in myeloma cells, and provide an additional rationale for the development of therapeutic strategies that interrupt DKK1 to cure MM.

scholarly journals Regulation of Raf-1-dependent signaling during early Xenopus development.

1995 ◽  
Vol 15 (12) ◽  
pp. 6686-6693 ◽  
Author(s):  
A M MacNicol ◽  
A J Muslin ◽  
E L Howard ◽  
A Kikuchi ◽  
M C MacNicol ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Mapk Pathway ◽  
Mapk Signaling ◽  
Embryonic Cell ◽  
Cycle Progression ◽  
Mapk Activity ◽  
Cytostatic Factor ◽  
Differentiation And Proliferation

The Raf-1 gene product is activated in response to cellular stimulation by a variety of growth factors and hormones. Raf-1 activity has been implicated in both cellular differentiation and proliferation. We have examined the regulation of the Raf-1/MEK/MAP kinase (MAPK) pathway during embryonic development in the frog Xenopus laevis. We report that Raf-1, MEK, and MAPK activities are turned off following fertilization and remain undetectable up until blastula stages (stage 8), some 4 h later. Tight regulation of the Raf-1/MEK/MAPK pathway following fertilization is crucial for embryonic cell cycle progression. Inappropriate reactivation of MAPK activity by microinjection of oncogenic Raf-1 RNA results in metaphase cell cycle arrest and, consequently, embryonic lethality. Our findings demonstrate an absolute requirement, in vivo, for inactivation of the MAPK signaling pathway to allow normal cell cycle progression during the period of synchronous cell divisions which occur following fertilization. Further, we show that cytostatic factor effects are mediated through MEK and MAPK.

scholarly journals Differential Effects of HIV Protease Inhibitors on Release and Activation of Platelet-Derived TGF-β1: Potential Association with HIV-Linked CVD

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2341-2341
Author(s):  
Kouzbari Karim ◽  
Gostynska Sandra ◽  
Sonia Elhadad ◽  
Dube Pratibha ◽  
Jeffrey Laurence ◽  
...  
Keyword(s):  
Protease Inhibitors ◽  
Low Dose ◽  
Cardiac Fibrosis ◽  
Conflicts Of Interest ◽  
Platelet Rich Plasma ◽  
Minor Effect ◽  
The Impact ◽  
Tgf Β1 ◽  
In Vivo Assessment

Combination antiretroviral therapies (cART) have markedly reduced mortality in HIV infection. However, cardiovascular disease (CVD), including heart failure linked to fibrosis, remains a major cause of morbidity and mortality in HIV/cART patients. The magnitude of this risk increases with use of certain protease inhibitors (PI), but the underlying mechanism remains unclear. We showed that the PI ritonavir leads to increased plasma levels of the pro-fibrotic cytokine TGF-β1, cardiac dysfunction, and pathologic cardiac fibrosis in wild-type (wt) C57BL/6 mice. Mice with targeted depletion of platelet TGF-β1 had reduced cardiac fibrosis and partially preserved cardiac function following ritonavir exposure (Laurence, et al. PLoS One 2017;12:e0187185). Several groups have examined the effects of a variety of cART agents on agonist-induced platelet aggregation, but correlations with clinical CVD are weak. Since platelets are a rich source of TGF-β1, we hypothesized that ritonavir and other PIs linked clinically to an increased CVD risk directly activate platelets to release TGF-β1 and activate latent (L)TGF-β1 to initiate signaling for organ fibrosis. We examined the impact of clinically relevant doses of ritonavir, alone and in combination with two other contemporary PIs, atazanavir and darunavir, which are currently used along with low dose ritonavir in so-called PI-boosted cART regimens. We incubated human platelet-rich plasma and washed platelets with PIs alone or in combinations at various doses for 10 min at 37°C in a platelet aggregometer (BioData. Corp). Total and active TGF-β1 levels were measured by ELISA. For in vivo assessment, we treated wt mice with a low dose of ritonavir, as used in PI-boosted cART, and measured the levels of plasma TGF-β1 by ELISA, and TGF-β1 signaling in tissues by immunofluorescence imaging for pSmad2. We found that ritonavir dose-dependently increased total TGF-β1 release from freshly-isolated platelet-rich plasma and washed human platelets. This release was blocked by ceefurin-1 and MK517, potent inhibitors of the ATP binding cassette transporter ABCC4. Darunavir alone did not cause release of TGF-β1, and did not alter significantly ritonavir-induced TGF-β1 release (Figure-1A). Atazanavir alone did induce release of TGF-β1 from platelets and did not affect the extent of such release induced by ritonavir (Figure-1A). Since total TGF-β1 released from platelets must be activated in order to signal, we tested whether these PIs could activate LTGF-β1. Ritonavir alone, in low dose, activated TGF-β1 by 4-5-fold (Fig-1B). Darunavir alone did not activate LTGF-β1, and had only a minor effect on ritonavir-induced TGF-β1 activation (Fig-1B). In marked contrast, while atazanavir also did not activate LTGF-β1, it significantly inhibited ritonavir-induced LTGF-β1 activation (Fig-1B). For in vivo assessment, wt mice were injected daily for 8 weeks with ritonavir, which dose-dependently increased plasma TGF-β1 levels (mean levels with vehicle 2.1 ng/ml; 6.4 ng/ml with 5 mg/kg ritonavir; 8.5 ng/ml with 10 mg/kg ritonavir). Increased TGF-β1 levels correlated with development of pathologic fibrosis and increased phosphorylated Smad signaling in hearts of ritonavir-treated vs. vehicle-treated mice. Clinical correlations with these in vitro and in vivo mouse studies are important. The fact that ritonavir effected both release and activation of platelet TGF-β1 is consistent with its ability to induce cardiac fibrosis and dysfunction in mice, and its association with accelerated CVD in HIV-infected individuals. Our findings that low dose ritonavir in combination with darunavir induced release and activation of platelet TGF-β1, whereas atazanavir blocked TGF-β1 activation, are consistent with the strong association of ritonavir-boosted darunavir, but not ritonavir-boosted atazanavir, with CVD in the setting of HIV (Ryom, et al. Lancet-HIV 2018;5:e291-e300). Future work will examine the effects of other contemporary cART agents, including cobicistat, which is currently replacing ritonavir in many PI-boosted therapies and some integrase-boosted regimens, on TGF-β1 release and activation, for which correlations with clinical CVD are not yet available. Identification of the mechanism of pathologic fibrosis in the heart, and potentially other organs affected by certain cART regimens, such as the kidney, may suggest specific therapeutic interventions. Disclosures No relevant conflicts of interest to declare.

scholarly journals Impact of Platelet Count on Bleeding in the Setting of Anti-Platelet Therapy

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 18-18
Author(s):  
Robert Hugh Lee ◽  
Wolfgang Bergmeier
Keyword(s):  
Real Time ◽  
Conflicts Of Interest ◽  
Thrombotic Event ◽  
Platelet Inhibition ◽  
Intravital Imaging ◽  
Severe Thrombocytopenia ◽  
Platelet Counts ◽  
Anti Platelet Therapy ◽  
The Impact

Anti-platelet therapy (APT) is used for secondary prevention of thrombosis. The most commonly prescribed anti-platelet drugs are aspirin and P2Y12 inhibitors, including clopidogrel, prasugrel and ticagrelor. Dual anti-platelet therapy (DAPT) consisting of aspirin and a P2Y12 inhibitor is often used in the first 1-12 months after an initial thrombotic event and has a greater anti-thrombotic effect than single agents, but is also associated with a higher risk of bleeding. Due to this risk of hemorrhage, the appropriate use of DAPT in patients requiring percutaneous coronary intervention (PCI) with baseline or periprocedural thrombocytopenia remains unclear. To study the impact of thrombocytopenia on bleeding with APT, we used intravital imaging in a murine hemostasis model and adoptive platelet transfer to generate mice with specific platelet counts with or without platelet inhibition. To generate experimental mice, we used transgenic mice in which platelets express a chimeric GPIb receptor with the extracellular domain replaced with a domain of the human IL-4R (hIL-4R/GPIb-Tg). Endogenous platelets were depleted by injection of anti-hIL-4R antibody, and the recipient mice were then transfused with wild-type (WT) platelets from donor mice treated, or not, with single or dual APT (aspirin 20 mg/kg; clopidogrel 25 mg/kg) to achieve specific platelet counts ranging from 50,000 to 400,000 platelets/μL. We also compared these mice with WT mice (with normal platelet counts, ~1,200,000 platelets/μL) treated with APT. Platelet inhibition was confirmed prior to performing in vivo experiments. Hemostasis was determined by intravital imaging in our saphenous vein laser injury model, in which a 50 μm injury was induced by laser ablation. Real-time top-down epifluorescence imaging was used to determine time to initial hemostasis, rebleeding events, and platelet and fibrin accumulation. In each mouse, 3-5 injuries were induced at different sites and each injury was visualized for 10 minutes. Following real-time imaging, spinning disk confocal Z-stacks of platelet plugs were obtained for 3D reconstruction to compare platelet plug volume. In untreated WT mice, hemostasis was achieved in ~20 seconds. In WT mice treated with DAPT, initial hemostasis was often rapidly achieved but this was followed by significant rebleeding events. Paradoxically, platelet accumulation was increased in WT + DAPT mice due to extravascular accumulation of platelets which occurred during bleeding. However, in plugs that stabilized, plug volume was reduced in WT + DAPT mice. In hIL-4R/GPIb-Tg mice with reduced platelet counts, untreated platelets were able to form a stable hemostatic plug even at 50,000/μL, although time to hemostasis was slightly prolonged. However, as platelet counts decreased in mice with DAPT-treated platelets, initial hemostasis became more prolonged and many injuries never achieved initial hemostasis. These results suggest that DAPT may not be safe in the setting of severe thrombocytopenia. Disclosures No relevant conflicts of interest to declare.

scholarly journals An Integration of Network Pharmacology and Experimental Verification to Investigate the Mechanism of Guizhi to Treat Nephrotic Syndrome

2021 ◽  
Vol 12 ◽  
Author(s):  
Dan He ◽  
Qiang Li ◽  
Guangli Du ◽  
Guofeng Meng ◽  
Jijia Sun ◽  
...  
Keyword(s):  
Nephrotic Syndrome ◽  
Molecular Docking ◽  
Protein Expression ◽  
Signaling Pathway ◽  
P38 Mapk ◽  
Experimental Verification ◽  
Active Component ◽  
Mapk Signaling

Background: Guizhi has the pharmacological activity of anti-inflammatory. However, the effect mechanism of Guizhi against nephrotic syndrome (NS) remains unclear. A network pharmacological approach with experimental verification in vitro and in vivo was performed to investigate the potential mechanisms of Guizhi to treat NS.Methods: Active compounds and potential targets of Guizhi, as well as the related targets of NS were obtained from the public databases. The intersecting targets of Guizhi and NS were obtained through Venny 2.1.0. The key targets and signaling pathways were determined by protein-protein interaction (PPI), genes ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analysis. And the overall network was constructed with Cytoscape. Molecular docking verification was carried out by AutoDock Vina. Finally, in vitro and in vivo experiments were performed to verify the mechanism of Guizhi to treat NS.Results: 63 intersecting targets were obtained, and the top five key targets mainly involed in NF- Kappa B and MAPK signaling pathway. In the overall network, cinnamaldehyde (CA) was the top one active compound with the highest degree value. The molecular docking showed that the top five key targets were of good binding activity with the active components of Guizhi. To in vitro experiment, CA, the main active component of Guizhi, inhibited the secretion of IL-1β, IL-6, TNF-α in LPS challenged RAW264.7 cells, and down regulated the protein expression of p-NF-κB p65 and p-p38 MAPK in LPS challenged RAW264.7 cells. In vitro experiment showed that, 24 urinary protein and renal function were increased in ADR group. To western blot, CA down regulated the protein expression of p-p38 MAPK in rats of adriamycin-induced nephropathy.Conclusion: CA might be the main active component of Guizhi to treat NS, and the underlying mechanism might mainly be achieved by inhibiting MAPK signaling pathway.

Mechanisms of bone destruction in multiple myeloma: the importance of an unbalanced process in determining the severity of lytic bone disease.

1989 ◽  
Vol 7 (12) ◽  
pp. 1909-1914 ◽  
Author(s):  
R Bataille ◽  
D Chappard ◽  
C Marcelli ◽  
P Dessauw ◽  
J Sany ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Resorption ◽  
Bone Formation ◽  
Bone Mass ◽  
Bone Remodeling ◽  
Cell Mass ◽  
Bone Destruction ◽  
Myeloma Cell ◽  
Bone Lesions ◽  
Mass Reduction

In order to clarify the mechanisms involved in the occurrence of lytic bone lesions (BL) in multiple myeloma (MM), we have compared the presenting myeloma-induced histological bone changes of 14 previously untreated MM patients with lytic BL with those of seven MM patients lacking lytic BL at presentation despite similar myeloma cell mass. A major unbalanced bone remodeling (increased bone resorption with normal to low bone formation) was the characteristic feature of patients presenting lytic BL. Furthermore, this unbalanced process was associated with a significant reduction of bone mass. Unexpectedly, a balanced bone remodeling (increase of both bone resorption and bone formation, without bone mass reduction) rather than a true lack of an excessive bone resorption was the usual feature of patients lacking lytic BL. Our current work clearly shows that a majority (72%) of patients with MM present an important unbalanced bone remodeling at diagnosis, leading to bone mass reduction and bone destruction (unbalanced MM). Some patients (20%) retain a balanced bone remodeling with initial absence of bone destruction (balanced MM). Few (8%) patients have pure osteoblastic MM without bone destruction.

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