scholarly journals A Novel Role of Numb as A Regulator of Pro-inflammatory Cytokine Production in Macrophages in Response to Toll-like Receptor 4

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Patipark Kueanjinda ◽  
Sittiruk Roytrakul ◽  
Tanapat Palaga
Keyword(s):  
Notch Signaling ◽  
P38 Mapk ◽  
Inflammatory Responses ◽  
Notch Signaling Pathway ◽  
Negative Regulator ◽  
Mrna Levels ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Murine Bone Marrow

Abstract Activation of macrophages triggers the release of pro-inflammatory cytokines leading to inflammation. Numb is a negative regulator of Notch signaling, but the role of Numb in macrophages is not fully understood. In this study, the role of Numb as a regulator of inflammatory responses in macrophages was investigated. Murine bone marrow-derived macrophages, in which expression of Numb was silenced, secreted significantly less TNFα, IL-6 and IL-12 and more IL-10 upon activation by lipopolysaccharide (LPS), a ligand for Toll-like receptor 4 (TLR4), despite increased Notch signaling. The Tnfα mRNA levels both in Numb-deficient and wild-type macrophages were not significantly different, unlike those of Il6 and Il12-p40. In Numb-deficient macrophages, the Tnfα mRNAs were degraded at faster rate, compared to those in control macrophages. Activation of p38 MAPK and NF-κΒ p65 were compromised in activated Numb deficient macrophages. Numb was found to interact with the E3 ubiquitin ligase, Itch, which reportedly regulates p38 MAPK. In addition, blocking the Notch signaling pathway in activated, Numb-deficient macrophages did not further reduce TNFα levels, suggesting a Notch-independent role for Numb. A proteomics approach revealed a novel funciton for Numb in regulating complex signaling cascades downstream of TLRs, partially involving Akt/NF-κB p65/p38 MAPK in macrophages.

Critical role of toll-like receptor 4 (TLR4) in ricin toxin-induced inflammatory responses in macrophages

2020 ◽  
Vol 321 ◽  
pp. 54-60 ◽  
Author(s):  
Mingxin Dong ◽  
Haotian Yu ◽  
Yan Wang ◽  
Chengbiao Sun ◽  
Ying Chang ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Critical Role ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Ricin Toxin

scholarly journals Macrophage glucocorticoid receptors regulate Toll-like receptor 4–mediated inflammatory responses by selective inhibition of p38 MAP kinase

Blood ◽  
2007 ◽  
Vol 109 (10) ◽  
pp. 4313-4319 ◽  
Author(s):  
Sandip Bhattacharyya ◽  
Diane E. Brown ◽  
Judson A. Brewer ◽  
Sherri K. Vogt ◽  
Louis J. Muglia
Keyword(s):  
Map Kinase ◽  
P38 Mapk ◽  
Glucocorticoid Receptors ◽  
Inflammatory Responses ◽  
Ex Vivo ◽  
Specific Inhibitor ◽  
P38 Map Kinase ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Map Kinase Phosphatase

Abstract To explore the role of glucocorticoids in regulation of kinase pathways during innate immune responses, we generated mice with conditional deletion of glucocorticoid receptor (GR) in macrophages (MGRKO). Activation of toll-like receptor 4 (TLR4) by lipopolysaccharide (LPS) caused greater mortality and cytokine production in MGRKO mice than in controls. Ex vivo, treatment with dexamethasone (Dex) markedly inhibited LPS-mediated induction of inflammatory genes in control but not GR-deficient macrophages. We show that Dex inhibits p38 MAPK, but not PI3K/Akt, ERK, or JNK, in control macrophages. Associated with p38 inhibition, Dex induced MAP kinase phosphatase-1 (MKP-1) in control, but not MGRKO, macrophages. Consistent with the ex vivo studies, treatment with a p38 MAPK–specific inhibitor resulted in rescue of MGRKO mice from LPS-induced lethality. Taken together, we identify p38 MAPK and its downstream targets as essential for GR-mediated immunosuppression in macrophages.

scholarly journals THE ROLE OF MRNA LEVEL OF THE NOTCH SIGNALING PATHWAY GENES IN INDUCED RAT LIVER FIBROGENESIS

2021 ◽  
Vol 20 (2) ◽  
pp. 25-37
Author(s):  
A.T. Shchastniy ◽  
◽  
E.I. Lebedeva ◽  
A.S. Babenka ◽  
◽  
...  
Keyword(s):  
Notch Signaling ◽  
Signaling Pathway ◽  
Rat Liver ◽  
Mrna Level ◽  
Notch Pathway ◽  
Notch Signaling Pathway ◽  
Mrna Levels ◽  
Starting Point ◽  
Liver Fibrogenesis

Objectives. To study the role of mRNA level of the Notch signaling pathway genes in induced rat liver fibrogenesis. Material and methods. Fibrosis followed by the transition to liver cirrhosis in rats of Wistar line was induced with thioacetamide at a dose of 200 mg/kg of animal body weight twice a week for 17 weeks. The rats were randomized into 9 groups of 12 animals each. The mRNA level of the Notch signaling pathway genes was assessed by real-time PCR. The notch1, notch2, yap1 and hes1 genes were used as molecular targets. Microscopic analysis of histological preparations was performed using the OLYMPUS BX51 microscope. The degree of fibrosis was assessed according to the scale of Ishak K.G. Results. The study of the classical transcription factor of the Notch signaling pathway, hes1, revealed its very low and stable activity in all studied samples. The analysis of relative dynamics of the mRNA level of the notch1, notch2, and yap1 genes made it possible to determine marked changes in their levels at the point of transition from the normal state of liver tissues to the development of fibrosis. Conclusions. Within the framework of this study, the hes1 gene is not a target of the Notch pathway and can be used as a reference gene. The noted decrease in the mRNA level of the yap1 gene, probably, inhibits the compensatory-restorative processes in the liver, activates the stellate cells, and promotes the transformation of fibrosis into cirrhosis. In addition, it has been found that the revealed fluctuations in the mRNA levels of the notch1 and yap1 genes in relation to the starting point (there are no changes in the liver tissue) quite accurately describe the period of the onset of the transition of advanced fibrosis to cirrhosis. In this regard, they can be considered as potential markers of the transition of fibrosis to cirrhosis.

scholarly journals Induction of TNF-α and MnSOD by endotoxin: role of membrane CD14 and Toll-like receptor-4

2001 ◽  
Vol 280 (6) ◽  
pp. C1422-C1430 ◽  
Author(s):  
Min-Fu Tsan ◽  
Robert N. Clark ◽  
Sanna M. Goyert ◽  
Julie E. White
Keyword(s):  
Manganese Superoxide Dismutase ◽  
Nuclear Factor Κb ◽  
Peritoneal Macrophages ◽  
Mrna Levels ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Potent Inducer ◽  
Tnf Α ◽  
Tlr4 Gene

Endotoxin (LPS) is a potent inducer of tumor necrosis factor-α (TNF-α) and manganese superoxide dismutase (MnSOD). Recent evidence suggests that LPS induction of TNF-α and MnSOD mRNAs is mediated through distinct intracellular signal transduction pathways. Membrane CD14 (mCD14) and Toll-like receptor-4 (TLR4) mediate LPS induction of TNF-α in macrophages. In the current study, we evaluated the role of mCD14 and TLR4 in LPS induction of MnSOD using peritoneal macrophages from CD14 knockout (CD14-KO) mice and mice with the Tlr4 gene point mutation (C3H/HeJ) or deletion (C57BL/10ScCr). We studied mCD14-dependent (1 and 10 ng/ml) and mCD14-independent (1,000 ng/ml) concentrations of LPS. Compared with control (BALB/c) macrophages, LPS at 1 and 10 ng/ml failed to induce TNF-α or MnSOD mRNA in CD14-KO macrophages. However, LPS at 1,000 ng/ml induced TNF-α and MnSOD mRNAs equally in macrophages from CD14-KO and control mice. LPS (1, 10, or 1,000 ng/ml) failed to induce TNF-α or MnSOD mRNA and failed to activate nuclear factor-κB in C3H/HeJ or C57BL/10ScCr macrophages. Measurements of TNF-α and MnSOD enzyme activity paralleled TNF-α and MnSOD mRNA levels. These data demonstrate that, like TNF-α, induction of MnSOD by LPS is mediated by mCD14 and TLR4 in murine macrophages.

Hes-1-targeting siRNA inhibits the maturation of murine myeloid-derived dendritic cells

2013 ◽  
Vol 8 (11) ◽  
pp. 1102-1111
Author(s):  
Guoliang Chen ◽  
Chunyan Yu ◽  
Feiyue Xing ◽  
Pengtao You ◽  
Jingfang Di ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Notch Signaling ◽  
Signaling Pathway ◽  
Critical Role ◽  
Specific Inhibitor ◽  
Notch Signaling Pathway ◽  
Murine Bone Marrow ◽  
Mhc Ii ◽  
Pathway Activation

AbstractActivation of Notch by Jagged-1 may plays a pivotal role in maturation of dendritic cells (DCs), but the mechanism has not been completely defined. In the present study, Hes-1 (Hairy/enhancer-of-split)-targeting siRNA was used to confirm a role of Jagged-1-Notch signaling pathway activation in maturation of murine bone marrow-derived DCs and to search for a target that plays a critical role. The results showed that compared with the control, lipopolysaccharide or Zymosan A groups, Jagged-1 (a soluble Jagged 1/Fc chimera protein) effectively increased expression of Hes-1 and Deltex-1 mRNA, which could be reversed by DAPT (2, 4-diamino-5-phenylthiazole), a specific inhibitor of the Notch signaling pathway. Hes-1-targeting siRNA could successfully down-regulate the endogenous Hes-1 expression in the DCs. Concurrently, a significant down-regulation of CD40, CD80, CD86 and MHC-II expressions on the surface of the DCs was found with the reduction of IL-12 yielded by the DCs. Our results demonstrate that Hes-1-targeting siRNA can inhibit the maturation of the DCs induced by Jagged-1, indicating Hes-1 may be an important target of Notch signaling mediating the maturation of DCs.

Mesenteric artery responsiveness to acetylcholine and phenylephrine in cirrhotic rats challenged with endotoxin: the role of TLR4

2015 ◽  
Vol 93 (6) ◽  
pp. 475-483 ◽  
Author(s):  
Sattar Ostadhadi ◽  
Seyed-Mahdi Rezayat ◽  
Shahram Ejtemaei-Mehr ◽  
Seyed-Mohammad Tavangar ◽  
Vahid Nikoui ◽  
...  
Keyword(s):  
Mesenteric Artery ◽  
Low Dose ◽  
Vascular Dysfunction ◽  
Mrna Levels ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Vascular Bed ◽  
Duct Ligation ◽  
Immunohistochemical Studies

Cirrhosis is associated with vascular dysfunction and endotoxemia. These experiments were designed to investigate the hypothesis that the administration of a low-dose of lipopolysaccharide (LPS) worsens vascular dysfunction in rats subjected to bile-duct ligation (BDL), and to determine whether LPS initiates changes in vascular Toll-like receptor 4 (TLR4) expression. Four weeks after BDL, the animals were given an intraperitoneal injection of either saline or LPS (1.0 mg/kg body mass). Three hours later, the superior mesenteric artery was isolated, perfused, and then subjected to the vasoconstriction and vasodilatation effects of phenylephrine and acetylcholine, respectively. Our results show that phenylephrine-induced vasoconstriction decreased in the cirrhotic vascular bed (BDL rats) compared with the vascular bed of the sham-operated animals, and that the LPS injections in the cirrhotic (BDL) rats worsened this response. LPS injection administered to the sham-operated animals had no such effect. On the other hand, both the BDL procedure and the LPS injection increased acetylcholine-induced vasorelaxation, but LPS administration to the BDL rats had no effect on this response. The mRNA levels of TLR4 did not change, but immunohistochemical studies showed that TLR4 localization switched from the endothelium to vascular smooth muscle cells following chronic BDL. In conclusion, acute endotoxemia in cirrhotic rats is associated with hyporesponsiveness to phenylephrine and tolerance to the effects of acetylcholine. Altered localization of TLR4 may be responsible for these effects.

scholarly journals Crosstalk between NOTCH and AKT signaling during murine megakaryocyte lineage specification

Blood ◽  
2011 ◽  
Vol 118 (5) ◽  
pp. 1264-1273 ◽  
Author(s):  
Melanie G. Cornejo ◽  
Vinciane Mabialah ◽  
Stephen M. Sykes ◽  
Tulasi Khandan ◽  
Cristina Lo Celso ◽  
...  
Keyword(s):  
Stem Cell ◽  
Notch Signaling ◽  
Signaling Pathway ◽  
Hematopoietic Stem Cell ◽  
Stem Cell Differentiation ◽  
Notch Signaling Pathway ◽  
Developmental Pathways ◽  
Lineage Specification ◽  
Hematopoietic Stem

Abstract The NOTCH signaling pathway is implicated in a broad range of developmental processes, including cell fate decisions. However, the molecular basis for its role at the different steps of stem cell lineage commitment is unclear. We recently identified the NOTCH signaling pathway as a positive regulator of megakaryocyte lineage specification during hematopoiesis, but the developmental pathways that allow hematopoietic stem cell differentiation into the erythro-megakaryocytic lineages remain controversial. Here, we investigated the role of downstream mediators of NOTCH during megakaryopoiesis and report crosstalk between the NOTCH and PI3K/AKT pathways. We demonstrate the inhibitory role of phosphatase with tensin homolog and Forkhead Box class O factors on megakaryopoiesis in vivo. Finally, our data annotate developmental mechanisms in the hematopoietic system that enable a decision to be made either at the hematopoietic stem cell or the committed progenitor level to commit to the megakaryocyte lineage, supporting the existence of 2 distinct developmental pathways.

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