scholarly journals Toll-like receptor 4 restricts retinal progenitor cell proliferation

2008 ◽  
Vol 183 (3) ◽  
pp. 393-400 ◽  
Author(s):  
Ravid Shechter ◽  
Ayal Ronen ◽  
Asya Rolls ◽  
Anat London ◽  
Sharon Bakalash ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Postnatal Period ◽  
Negative Regulator ◽  
Early Postnatal Period ◽  
Toll Like Receptor ◽  
Tlr4 Expression ◽  
Toll Like Receptor 4 ◽  
Retinal Progenitor

Retinal neurogenesis ceases by the early postnatal period, although retinal progenitor cells (RPCs) persist throughout life. In this study, we show that in the mammalian eye, the function of Toll-like receptor 4 (TLR4) extends beyond regulation of the innate immune response; it restricts RPC proliferation. In TLR4-deficient mice, enhanced proliferation of cells reminiscent of RPCs is evident during the early postnatal period. In vitro experiments demonstrate that TLR4 acts as an intrinsic regulator of RPC fate decision. Increased TLR4 expression in the eye correlates with the postnatal cessation of cell proliferation. However, deficient TLR4 expression is not sufficient to extend the proliferative period but rather contributes to resumption of proliferation in combination with growth factors. Proliferation in vivo is inhibited by both MyD88-dependent and -independent pathways, similar to the mechanisms activated by TLR4 in immune cells. Thus, our study attributes a novel role to TLR4 as a negative regulator of RPC proliferation.

scholarly journals Serum Amyloid A1/Toll-Like Receptor-4 Axis, an Important Link between Inflammation and Outcome of TBI Patients

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 599
Author(s):  
Víctor Farré-Alins ◽  
Alejandra Palomino-Antolín ◽  
Paloma Narros-Fernández ◽  
Ana Belen Lopez-Rodriguez ◽  
Céline Decouty-Perez ◽  
...  
Keyword(s):  
Injury Severity ◽  
White Blood Cells ◽  
Serum Amyloid ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Important Link ◽  
Tlr4 Mrna ◽  
Serum Amyloid A1

Traumatic brain injury (TBI) is one of the leading causes of mortality and disability worldwide without any validated biomarker or set of biomarkers to help the diagnosis and evaluation of the evolution/prognosis of TBI patients. To achieve this aim, a deeper knowledge of the biochemical and pathophysiological processes triggered after the trauma is essential. Here, we identified the serum amyloid A1 protein-Toll-like receptor 4 (SAA1-TLR4) axis as an important link between inflammation and the outcome of TBI patients. Using serum and mRNA from white blood cells (WBC) of TBI patients, we found a positive correlation between serum SAA1 levels and injury severity, as well as with the 6-month outcome of TBI patients. SAA1 levels also correlate with the presence of TLR4 mRNA in WBC. In vitro, we found that SAA1 contributes to inflammation via TLR4 activation that releases inflammatory cytokines, which in turn increases SAA1 levels, establishing a positive proinflammatory loop. In vivo, post-TBI treatment with the TLR4-antagonist TAK242 reduces SAA1 levels, improves neurobehavioral outcome, and prevents blood–brain barrier disruption. Our data support further evaluation of (i) post-TBI treatment in the presence of TLR4 inhibition for limiting TBI-induced damage and (ii) SAA1-TLR4 as a biomarker of injury progression in TBI patients.

scholarly journals ORMDL1 is upregulated and associated with favorable outcome in colorectal cancer

2020 ◽  
Author(s):  
Qian Wang ◽  
Wanjun Liu ◽  
Si Chen ◽  
Qianxin Luo ◽  
Yichen Li ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Proliferation ◽  
Colony Formation ◽  
Transmembrane Protein ◽  
Cohort Analysis ◽  
Negative Regulator ◽  
Morphologic Change ◽  
Mesenchymal Transition

AbstractBackgroundORMDL1 gene encodes a transmembrane protein for endoplasmic reticulum and is known as crucial negative regulator for sphingolipid biogenesis. However, it has been rarely studied in tumor-related context. Therefore, its prognostic value and functional significance in colorectal cancer (CRC) remain to be explored.MethodsTCGA CRC cohort analysis, qRT-PCR, and immunohistochemistry (IHC) were used to examine the ORMDL1 expression level. The association between ORMDL1 expression and various clinical characteristics were analyzed by Chi-square tests. CRC patients’ overall survival (OS) was analyzed by Kaplan-Meier analysis. In vitro and in vivo cell-based assays were performed to explore the role of ORMDL1 in cell proliferation, invasion and migration. Transcriptional changes of cells either with ORMDL1 knockdowned or overexpressed were compared and analyzed.ResultsORMDL1 was upregulated in CRC tissues either in TCGA cohort or in our cohort. Interestingly, its expression was significantly lower in patients with metastasis compared to patients without metastasis, and high expression group had longer OS than low expression group. Knockdown of ORMDL1 expression can promote proliferation, colony formation and invasion, while attenuate migration in CRC cell lines. In opposite, forced overexpression of ORMDL1 reduced cell proliferation, colony formation and invasion, while enhanced cell migration. Epithelial-to-mesenchymal transition (EMT) related genes were enriched among differentially expressed genes when ORMDL1 was knockdowned in cells, which was consistent with morphologic change by microscopy observation. Finally, stable knockdown of ORMDL1 can promote cancer cell proliferation in vivo to some extent.ConclusionORMDL1 is upregulated and may serve as biomarker to predict favourable outcome in colorectal cancer.

scholarly journals Micrococcus luteus Teichuronic Acids Activate Human and Murine Monocytic Cells in a CD14- and Toll-Like Receptor 4-Dependent Manner

2001 ◽  
Vol 69 (4) ◽  
pp. 2025-2030 ◽  
Author(s):  
Shuhua Yang ◽  
Shunji Sugawara ◽  
Toshihiko Monodane ◽  
Masahiro Nishijima ◽  
Yoshiyuki Adachi ◽  
...  
Keyword(s):  
Lipid A ◽  
Micrococcus Luteus ◽  
Dependent Manner ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Necrosis Factor Alpha ◽  
Monocytic Cells ◽  
Tnf Α

ABSTRACT Teichuronic acid (TUA), a component of the cell walls of the gram-positive organism Micrococcus luteus (formerlyMicrococcus lysodeikticus), induced inflammatory cytokines in C3H/HeN mice but not in lipopolysaccharide (LPS)-resistant C3H/HeJ mice that have a defect in the Toll-like receptor 4 (TLR4) gene, both in vivo and in vitro, similarly to LPS (T. Monodane, Y. Kawabata, S. Yang, S. Hase, and H. Takada, J. Med. Microbiol. 50:4–12, 2001). In this study, we found that purified TUA (p-TUA) induced tumor necrosis factor alpha (TNF-α) in murine monocytic J774.1 cells but not in mutant LR-9 cells expressing membrane CD14 at a lower level than the parent J774.1 cells. The TNF-α-inducing activity of p-TUA in J774.1 cells was completely inhibited by anti-mouse CD14 monoclonal antibody (MAb). p-TUA also induced interleukin-8 (IL-8) in human monocytic THP-1 cells differentiated to macrophage-like cells expressing CD14. Anti-human CD14 MAb, anti-human TLR4 MAb, and synthetic lipid A precursor IVA, an LPS antagonist, almost completely inhibited the IL-8-inducing ability of p-TUA, as well as LPS, in the differentiated THP-1 cells. Reduced p-TUA did not exhibit any activities in J774.1 or THP-1 cells. These findings strongly suggested that M. luteus TUA activates murine and human monocytic cells in a CD14- and TLR4-dependent manner, similar to LPS.

Pseudomonas aeruginosa Lipopolysaccharide Induces Osteoclastogenesis Through a Toll-Like Receptor 4 Mediated Pathway in Vitro and in Vivo

2007 ◽  
Vol 117 (5) ◽  
pp. 841-847 ◽  
Author(s):  
Lei Zhuang ◽  
Jae Y. Jung ◽  
Eric W. Wang ◽  
Patrick Houlihan ◽  
Lisette Ramos ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4

scholarly journals Leukocyte- and Platelet-Derived Microvesicle Interactions following In Vitro and In Vivo Activation of Toll-Like Receptor 4 by Lipopolysaccharide

PLoS ONE ◽  
2011 ◽  
Vol 6 (9) ◽  
pp. e25504 ◽  
Author(s):  
Jing Xiong ◽  
Virginia M. Miller ◽  
Larry W. Hunter ◽  
Yunman Li ◽  
Muthuvel Jayachandran
Keyword(s):  
Toll Like Receptor ◽  
Toll Like Receptor 4

scholarly journals Toll-Like Receptor 4 (TLR4) Expression Affects Schwann Cell Behavior in vitro

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Huanhuan Zhang ◽  
Zhiwei Shao ◽  
Yun Zhu ◽  
Lingyu Shi ◽  
Zhihao Li ◽  
...  
Keyword(s):  
Schwann Cell ◽  
Cell Behavior ◽  
Toll Like Receptor ◽  
Tlr4 Expression ◽  
Toll Like Receptor 4

194 A Non-Gluten Component of Wheat is a Strong Stimulator of Innate Immune Responses In Vitro and In Vivo and Acts via Toll Like Receptor 4

2010 ◽  
Vol 138 (5) ◽  
pp. S-36
Author(s):  
Yvonne Junker ◽  
Donatella Barisani ◽  
Daniel A. Leffler ◽  
Towia Libermann ◽  
Simon T. Dillon ◽  
...  
Keyword(s):  
Immune Responses ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4

Phosphoinositide 3-kinase is activated by MUC1 but not responsible for MUC1-induced suppression of Toll-like receptor 5 signaling

2007 ◽  
Vol 293 (3) ◽  
pp. L686-L692 ◽  
Author(s):  
Kosuke Kato ◽  
Wenju Lu ◽  
Hirofumi Kai ◽  
K. Chul Kim
Keyword(s):  
Cross Talk ◽  
Negative Regulator ◽  
Regulatory Subunit ◽  
Binding Motif ◽  
Toll Like Receptor ◽  
Akt Phosphorylation ◽  
Phosphoinositide 3 Kinase ◽  
Toll Like Receptor 5

MUC1 is a membrane-tethered mucin-like glycoprotein expressed on the surface of various mucosal epithelial cells as well as hematopoietic cells. Recently, we showed that MUC1 suppresses flagellin-induced Toll-like receptor (TLR) 5 signaling both in vivo and in vitro through cross talk with TLR5. In this study, we determined whether phosphoinositide 3-kinase (PI3K), a negative regulator of TLR5 signaling, is involved in the cross talk between MUC1 and TLR5 using various genetically modified epithelial cell lines. Our results showed 1) activation of MUC1 induced recruitment of the PI3K regulatory subunit p85 to the MUC1 cytoplasmic tail (CT) as well as Akt phosphorylation, 2) MUC1-induced Akt phosphorylation required the presence of Tyr20 within the PI3K binding motif of the MUC1 CT, and 3) mutation of Tyr20 or pharmacological inhibition of PI3K activation failed to block MUC1-induced suppression of TLR5 signaling. We conclude that whereas PI3K is downstream of MUC1 activation and negatively regulates TLR5 signaling, it is not responsible for MUC1-induced suppression of TLR5 signaling.

Vitamin D inhibits lipopolysaccharide-induced inflammatory response potentially through the Toll-like receptor 4 signalling pathway in the intestine and enterocytes of juvenile Jian carp (Cyprinus carpio var. Jian)

2015 ◽  
Vol 114 (10) ◽  
pp. 1560-1568 ◽  
Author(s):  
Jun Jiang ◽  
Dan Shi ◽  
Xiao-Qiu Zhou ◽  
Long Yin ◽  
Lin Feng ◽  
...  
Keyword(s):  
Vitamin D ◽  
Inflammatory Response ◽  
Mrna Expression ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Jian Carp ◽  
Pre Treatment ◽  
Inflammatory Effect

AbstractThe present study was conducted to investigate the anti-inflammatory effect of vitamin D both in juvenile Jian carp (Cyprinus carpio var. Jian) in vivo and in enterocytes in vitro. In primary enterocytes, exposure to 10 mg lipopolysaccharide (LPS)/l increased lactate dehydrogenase activity in the culture medium (P<0·05) and resulted in a significant loss of cell viability (P<0·05). LPS exposure increased (P<0·05) the mRNA expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-8), which was decreased by pre-treatment with 1,25-dihydroxyvitamin D (1,25D3) in a dose-dependent manner (P<0·05). Further results showed that pre-treatment with 1,25D3 down-regulated Toll-like receptor 4 (TLR4), myeloid differentiation primary response gene 88 (Myd88) and NF-κB p65 mRNA expression (P<0·05), suggesting potential mechanisms against LPS-induced inflammatory response. In vivo, intraperitoneal injection of LPS significantly increased TNF-α, IL-1β, IL-6 and IL-8 mRNA expression in the intestine of carp (P<0·05). Pre-treatment of fish with vitamin D3 protected the fish intestine from the LPS-induced increase of TNF-α, IL-1β, IL-6 and IL-8 mainly by downregulating TLR4, Myd88 and NF-κB p65 mRNA expression (P<0·05). These observations suggest that vitamin D could inhibit LPS-induced inflammatory response in juvenile Jian carp in vivo and in enterocytes in vitro. The anti-inflammatory effect of vitamin D is mediated at least in part by TLR4-Myd88 signalling pathways in the intestine and enterocytes of juvenile Jian carp.

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