scholarly journals CD14 dependence of TLR4 endocytosis and TRIF signaling displays ligand specificity and is dissociable in endotoxin tolerance

2015 ◽  
Vol 112 (27) ◽  
pp. 8391-8396 ◽  
Author(s):  
Rajesh Rajaiah ◽  
Darren J. Perkins ◽  
Derek D. C. Ireland ◽  
Stefanie N. Vogel
Keyword(s):  
Signaling Pathways ◽  
Lipid A ◽  
Endotoxin Tolerance ◽  
Murine Macrophages ◽  
Receptor Endocytosis ◽  
Downstream Signaling ◽  
Tnf Α ◽  
Signaling Axis ◽  
Myeloid Differentiation Factor ◽  
Cluster Of Differentiation

Dimerization of Toll-like receptor 4 (TLR4)/myeloid differentiation factor 2 (MD2) heterodimers is critical for both MyD88- and TIR-domain–containing adapter-inducing IFN-β (TRIF)-mediated signaling pathways. Recently, Zanoni et al. [(2011)Cell147(4):868–880] reported that cluster of differentiation 14 (CD14) is required for LPS-/Escherichia coli- induced TLR4 internalization into endosomes and activation of TRIF-mediated signaling in macrophages. We confirmed their findings with LPS but report here that CD14 is not required for receptor endocytosis and downstream signaling mediated by TLR4/MD2 agonistic antibody (UT12) and synthetic small-molecule TLR4 ligands (1Z105) in murine macrophages. CD14 deficiency completely ablated the LPS-induced TBK1/IRF3 signaling axis that mediates production of IFN-β in murine macrophages without affecting MyD88-mediated signaling, including NF-κB, MAPK activation, and TNF-α and IL-6 production. However, neither the MyD88- nor TRIF-signaling pathways and their associated cytokine profiles were altered in the absence of CD14 in UT12- or 1Z105-treated murine macrophages. Eritoran (E5564), a lipid A antagonist that binds the MD2 “pocket,” completely blocked LPS- and 1Z105-driven, but not UT12-induced, TLR4 dimerization and endocytosis. Furthermore, TLR4 endocytosis is induced in macrophages tolerized by exposure to either LPS or UT12 and is independent of CD14. These data indicate that TLR4 receptor endocytosis and the TRIF-signaling pathway are dissociable and that TLR4 internalization in macrophages can be induced by UT12, 1Z105, and during endotoxin tolerance in the absence of CD14.

Evidence for Endogenous C1q Modulates TNF-α Receptor Synthesis and Autocrine Binding of TNF-α Associated with Lipid A Activation of Murine Macrophages for Nitric Oxide Production

1996 ◽  
Vol 170 (1) ◽  
pp. 34-40 ◽  
Author(s):  
Hong Jiang ◽  
John A. Rummage ◽  
Charles A. Stewart ◽  
Mary J. Herriott ◽  
Irina Kolosova ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Lipid A ◽  
Nitric Oxide Production ◽  
Murine Macrophages ◽  
Oxide Production ◽  
Tnf Α

scholarly journals Differential Induction of the Toll-Like Receptor 4-MyD88-Dependent and -Independent Signaling Pathways by Endotoxins

2005 ◽  
Vol 73 (5) ◽  
pp. 2940-2950 ◽  
Author(s):  
Susu M. Zughaier ◽  
Shanta M. Zimmer ◽  
Anup Datta ◽  
Russell W. Carlson ◽  
David S. Stephens
Keyword(s):  
Nitric Oxide ◽  
Signaling Pathways ◽  
Lipid A ◽  
Raw 264.7 ◽  
Receptor Complex ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Nitric Oxide Release ◽  
Tnf Α ◽  
Dependent Pathway

ABSTRACT The biological response to endotoxin mediated through the Toll-like receptor 4 (TLR4)-MD-2 receptor complex is directly related to lipid A structure or configuration. Endotoxin structure may also influence activation of the MyD88-dependent and -independent signaling pathways of TLR4. To address this possibility, human macrophage-like cell lines (THP-1, U937, and MM6) or murine macrophage RAW 264.7 cells were stimulated with picomolar concentrations of highly purified endotoxins. Harvested supernatants from previously stimulated cells were also used to stimulate RAW 264.7 or 23ScCr (TLR4-deficient) macrophages (i.e., indirect induction). Neisseria meningitidis lipooligosaccharide (LOS) was a potent direct inducer of the MyD88-dependent pathway molecules tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), monocyte chemoattractant protein 1 (MCP-1), macrophage inflammatory protein 3α (MIP-3α), and the MyD88-independent molecules beta interferon (IFN-β), nitric oxide, and IFN-γ-inducible protein 10 (IP-10). Escherichia coli 55:B5 and Vibrio cholerae lipopolysaccharides (LPSs) at the same pmole/ml lipid A concentrations induced comparable levels of TNF-α, IL-1β, and MIP-3α, but significantly less IFN-β, nitric oxide, and IP-10. In contrast, LPS from Salmonella enterica serovars Minnesota and Typhimurium induced amounts of IFN-β, nitric oxide, and IP-10 similar to meningococcal LOS but much less TNF-α and MIP-3α in time course and dose-response experiments. No MyD88-dependent or -independent response to endotoxin was seen in TLR4-deficient cell lines (C3H/HeJ and 23ScCr) and response was restored in TLR4-MD-2-transfected human embryonic kidney 293 cells. Blocking the MyD88-dependent pathway by DNMyD88 resulted in significant reduction of TNF-α release but did not influence nitric oxide release. IFN-β polyclonal antibody and IFN-α/β receptor 1 antibody significantly reduced nitric oxide release. N. meningitidis endotoxin was a potent agonist of both the MyD88-dependent and -independent signaling pathways of the TLR4 receptor complex of human macrophages. E. coli 55:B5 and Vibrio cholerae LPS, at the same picomolar lipid A concentrations, selectively induced the MyD88-dependent pathway, while Salmonella LPS activated the MyD88-independent pathway.

Candida tropicalis induces pro-inflammatory cytokine production, NF-κB and MAPKs pathways regulation, and dectin-1 activation

2018 ◽  
Vol 64 (12) ◽  
pp. 937-944 ◽  
Author(s):  
Zhimin Duan ◽  
Qing Chen ◽  
Rong Zeng ◽  
Leilei Du ◽  
Caixia Liu ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Inflammatory Cytokine ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Mapk Signaling ◽  
Dependent Manner ◽  
Peripheral Blood Mononuclear ◽  
Downstream Signaling ◽  
Tnf Α ◽  
Mitogen Activated Protein

The prevalence of Candida infection induced by non-albicans Candida (NAC) species is increasing. However, as a common NAC species, C. tropicalis has received much less study in terms of host immunity than C. albicans has. In this study, we evaluated the pro-inflammatory cytokine responses evoked by C. tropicalis and determined whether dectin-1 and downstream NF-κB and mitogen-activated protein kinases (MAPKs) signaling pathways played roles in inflammation in human peripheral blood mononuclear cells (PBMCs) and THP-1 macrophage-like cells. Exposure of PBMCs and THP-1 macrophage-like cells to C. tropicalis led to the enhanced gene expression and secretion of TNF-α and IL-6 in a time- and dose-dependent manner. THP-1 macrophage-like cells being challenged by C. tropicalis resulted in the activation of the NF-κB, p38, and ERK1/2 MAPK signaling pathways. We also found that the expression of dectin-1 was increased with C. tropicalis treatment. These data reveal that dectin-1 may play a role in sensing the inflammation response induced by C. tropicalis and that NF-κB and MAPK are involved in the downstream signaling pathways in macrophages.

scholarly journals Inhibition of cAMP/PKA/CREB Signaling Axis Improves Fibroblast Plasticity for Direct Cardiac Reprogramming

2021 ◽  
Author(s):  
Emre Bektik ◽  
Yu Sun ◽  
Adrienne Dennis ◽  
Phraew Sakon ◽  
Dandan Yang ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Primary Cell Culture ◽  
Myofibroblast Differentiation ◽  
Camp Concentration ◽  
Cultured Fibroblasts ◽  
Downstream Signaling ◽  
Upstream Regulator ◽  
Reprogramming Efficiency ◽  
Signaling Axis

Direct cardiac reprogramming of fibroblasts into induced cardiomyocytes (iCMs) is a promising approach but remains a challenging technology of regenerative medicine for damaged myocardium. Efforts have been focused on improving the efficiency by understanding fundamental mechanisms. One of the major challenges is that the plasticity of cultured fibroblast varies batch to batch with unknown mechanisms. Here, we noticed that a portion of in vitro cultured fibroblasts have been activated to differentiate into myofibroblasts, marked by the expression of αSMA, even in the primary cell culture of tissues. Both forskolin, which activates adenylyl cyclase and increases cAMP concentration, and TGFbeta inhibitor SB431542 can efficiently suppress myofibroblast differentiation of cultured fibroblasts. However, SB431542 improved but forskolin blocked iCM reprogramming of fibroblasts that were infected with retroviruses of Gata4, Mef2c and Tbx5 (GMT). Moreover, inhibitors of cAMP downstream signaling pathways, PKA or CREB-CBP, significantly improved the efficiency of iCM reprogramming. Consistently, inhibition of p38/MAPK, another upstream regulator of CREB-CBP, also improved reprogramming efficiency. We then investigated if inhibition of these signaling pathways in primary cultured fibroblast could improve their plasticity for reprogramming, and found that preconditioning of cultured fibroblasts with CREB-CBP inhibitor significantly improved the cellular plasticity of fibroblasts to be reprogrammed, yielding ~2-fold amount of reprogrammed iCMs compared to that of untreated control cells. In conclusion, suppression of cAMP/PKA/CREB signaling axis improves fibroblast plasticity for direct cardiac reprogramming.

scholarly journals Lipopolysaccharide and Its Analog Antagonists Display Differential Serum Factor Dependencies for Induction of Cytokine Genes in Murine Macrophages

1998 ◽  
Vol 66 (6) ◽  
pp. 2562-2569 ◽  
Author(s):  
Pin-Yu Perera ◽  
Nilofer Qureshi ◽  
William J. Christ ◽  
Peter Stütz ◽  
Stefanie N. Vogel
Keyword(s):  
Lipid A ◽  
Rhodobacter Capsulatus ◽  
Structural Analog ◽  
Synthetic Analog ◽  
Necrosis Factor Alpha ◽  
Cytokine Genes ◽  
Murine Macrophages ◽  
Proinflammatory Mediators ◽  
Low Concentrations ◽  
Tnf Α

Monocytes/macrophages play a central role in mediating the effects of lipopolysaccharide (LPS) derived from gram-negative bacteria by the production of proinflammatory mediators. Recently, it was shown that the expression of cytokine genes for tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and interferon-inducible protein-10 (IP-10) by murine macrophages in response to low concentrations of LPS is entirely CD14 dependent. In this report, we show that murine macrophages respond to low concentrations of LPS (≤2 ng/ml) in the complete absence of serum, leading to the induction of TNF-α and IL-1β genes. In contrast to the TNF-α and IL-1β genes, the IP-10 gene is poorly induced in the absence of serum. The addition of recombinant human soluble CD14 (rsCD14) had very little effect on the levels of serum-free, LPS-induced TNF-α, IL-1β, and IP-10 genes. In contrast, the addition of recombinant human LPS-binding protein (rLBP) had opposing effects on the LPS-induced TNF-α or IL-1β and IP-10 genes. rLBP inhibited LPS-induced TNF-α and IL-1β genes, while it reconstituted IP-10 gene expression to levels induced in the presence of serum. These results provide further evidence that the induction of TNF-α or IL-1β genes occurs via a pathway that is distinct from one that leads to the induction of the IP-10 gene and that the pathways diverge at the level of the initial interaction between LPS and cellular CD14. Additionally, the results presented here indicate that LPS structural analog antagonists Rhodobacter sphaeroides diphosphoryl lipid A and SDZ 880.431 are able to inhibit LPS-induced TNF-α and IL-1β in the absence of serum, while a synthetic analog of Rhodobacter capsulatus lipid A (B 975) requires both rsCD14 and rLBP to function as an inhibitor.

Effects of 3-Phenyl-Propenal on the Expression of Toll-Like Receptors and Downstream Signaling Components on Raw264.7 Murine Macrophages

2008 ◽  
Vol 36 (01) ◽  
pp. 159-169 ◽  
Author(s):  
Bao-Sheng Zhao ◽  
Hai-Ru Huo ◽  
Yue-Ying Ma ◽  
Hong-Bin Liu ◽  
Lan-Fang Li ◽  
...  
Keyword(s):  
Tumor Necrosis Factor Receptor ◽  
Immunofluorescence Assay ◽  
Antagonistic Effect ◽  
Poly I:C ◽  
Raw264.7 Cells ◽  
Toll Like Receptor ◽  
Downstream Signaling ◽  
Tnf Α ◽  
Myeloid Differentiation Factor ◽  
Signaling Components

3-phenyl-propenal is one of the principle compounds isolated from Guizhi (Ramulus Cinnamomi), the principal drug in Guizhi-Tang (GZT), a famous traditional Chinese medical formula. The aim of the present study was to investigate the effects of 3-phenyl-propenal on the expression of toll-like receptor 3 (TLR3), TLR4 and the downstream signaling components on Raw264.7 murine microphages. Raw264.7 cells were cultured in RPMI-1640 medium containing LPS (lipopolysaccharide) or poly (I:C) in the presence or absence of 3-phenyl-propenal. After 24-hour incubation, the medium was collected and the amount of TNF-α and IFN-β was measured by ELISA. mRNA expression of TLR3, TLR4, myeloid differentiation factor (MyD88), TRAF-6 (tumor necrosis factor receptor-associated), TRAM (toll-like receptor-associated molecule) and TRIF (TIR domain-containing adaptor inducing IFN-β) were analyzed by real-time PCR with SYBR green dye. Protein expression of TLR3 and TLR4 was analyzed by Western blotting and that of MyD88 and TRAF-6 was analyzed by immunofluorescence assay. The results indicate that LPS increased the expression of TLR4, MyD88, TRAF-6, TRAM and TRIF, but had no influence on TLR3, while poly (I:C) up-regulated the expression of TLR3, MyD88, TRAM and TRIF. 3-phenyl-propenal significantly decreased the expression of LPS-induced TLR4, MyD88, TRAF-6, while possessing no effect on LPS-induced TRAM and TRIF expression in Raw264.7 cells. When cells were stimulated by poly (I:C), 3-phenyl-propenal significantly decreased TLR3 and MyD88 expression. In conclusion, 3-phenyl-propenal blocked the over-expression of TLR3, TLR4, their downstream signaling components MyD88 and TRAF-6, which indicate that it had an antagonistic effect on TLR3 and TLR4.

The Impact of Royal Jelly against Hepatic Ischemia/Reperfusion-Induced Hepatocyte Damage in Rats: The Role of Cytoglobin, Nrf-2/HO-1/COX-4, and P38-MAPK/NF-κB-p65/TNF-α Signaling Pathways

2020 ◽  
Vol 14 (1) ◽  
pp. 88-100
Author(s):  
Fares E.M. Ali ◽  
Heba M. Saad Eldien ◽  
Nashwa A.M. Mostafa ◽  
Abdulrahman H. Almaeen ◽  
Mohamed R.A. Marzouk ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
P38 Mapk ◽  
Royal Jelly ◽  
Ischemia Reperfusion ◽  
Histopathological Changes ◽  
Down Regulation ◽  
Hepatic Ischemia ◽  
Tnf Α ◽  
Hepatic Ischemia Reperfusion ◽  
The Impact

Objective: The present study was conducted to elucidate the underlying molecular mechanism as well as the potential hepatoprotective effects of royal jelly (RJ) against hepatic ischemia/reperfusion (IR) injury. Methods: Rats were assigned into four groups; sham (received vehicle), IR (30 minutes ischemia and 45 minutes reperfusion), sham pretreated with RJ (200 mg/kg P.O.), and IR pretreated with RJ (200 mg/kg P.O.). The experiment has lasted for 28 days. Results: Hepatic IR significantly induced hepatic dysfunctions, as manifested by elevation of serum transaminases, ALP and LDH levels. Moreover, hepatic IR caused a significant up-regulation of P38-MAPK, NF-κB-p65, TNF-α and MDA levels along with marked down-regulation of Nrf-2, HO-1, COX-4, cytoglobin, IκBa, IL-10, GSH, GST and SOD levels. Additionally, marked histopathological changes were observed after hepatic IR injury. On the contrary, pretreatment with RJ significantly improved hepatic functions along with the alleviation of histopathological changes. Moreover, RJ restored oxidant/antioxidant balance as well as hepatic expressions of Nrf-2, HO-1, COX-4, and cytoglobin. Simultaneously, RJ significantly mitigated the inflammatory response by down-regulation of P38-MAPK, NF-κB-p65, TNF-α expression. Conclusion: The present results revealed that RJ has successfully protected the liver against hepatic IR injury through modulation of cytoglobin, Nrf-2/HO-1/COX-4, and P38-MAPK/NF-κB-p65/TNF-α signaling pathways.

scholarly journals Interplay Between SOX9, Wnt/β-Catenin and Androgen Receptor Signaling in Castration-Resistant Prostate Cancer

2019 ◽  
Vol 20 (9) ◽  
pp. 2066 ◽  
Author(s):  
Namrata Khurana ◽  
Suresh C. Sikka
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Signaling Pathways ◽  
Critical Role ◽  
Castration Resistant Prostate Cancer ◽  
Form Complex ◽  
Androgen Receptor Signaling ◽  
Castration Resistant ◽  
Signaling Axis

Androgen receptor (AR) signaling plays a key role not only in the initiation of prostate cancer (PCa) but also in its transition to aggressive and invasive castration-resistant prostate cancer (CRPC). However, the crosstalk of AR with other signaling pathways contributes significantly to the emergence and growth of CRPC. Wnt/β-catenin signaling facilitates ductal morphogenesis in fetal prostate and its anomalous expression has been linked with PCa. β-catenin has also been reported to form complex with AR and thus augment AR signaling in PCa. The transcription factor SOX9 has been shown to be the driving force of aggressive and invasive PCa cells and regulate AR expression in PCa cells. Furthermore, SOX9 has also been shown to propel PCa by the reactivation of Wnt/β-catenin signaling. In this review, we discuss the critical role of SOX9/AR/Wnt/β-catenin signaling axis in the development and progression of CRPC. The phytochemicals like sulforaphane and curcumin that can concurrently target SOX9, AR and Wnt/β-catenin signaling pathways in PCa may thus be beneficial in the chemoprevention of PCa.

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