scholarly journals DENGUE VIRUS ALTERS SIALIC ACID RESIDUES CONFIGURATION IN MACROPHAGES

2021 ◽  
Author(s):  
Javier Serrato-Salas ◽  
Isabel Cruz Zazueta ◽  
Jose Luis Montiel Hernandez ◽  
Judith Gonzalez Christen
Keyword(s):  
Sialic Acid ◽  
Virus Infection ◽  
Dengue Virus ◽  
Dengue Virus Infection ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Human Monocytic Cell Line ◽  
Human Monocytic Cell ◽  
Selective Mechanism

The activation of the innate immune response requires sialic acid residues removal. Nevertheless, it is unknown the role of these changes during the Dengue virus infection. We determine if during Dengue virus infection, the sialic acid residues alter on the macrophages. The human monocytic cell line THP-1 was differentiated into macrophages and were infected with Dengue virus. The changes in sialic acid were evaluated by lectin blot in the cellular lysate. The activity of neuraminidase was defined by RT-PCR and fluorescence assays. Macrophages infection with DENV-2 reduces α-2,6 sialic acid residues at 24 h, and α-2,3 sialic acid residues lower at 48 h in some proteins. Transcriptional profile and enzymatic activities of Neu-1 showed a narrow decrease. Sialic acid residues oscillation in varied conformations and times suggest a role of a selective mechanism to remove these residues. The lesser participation of Neu-1 in this process could be concomitant to other similar enzymes such as sialyl-transferases, or the phenomenon requires minimal activity to have a relevant biological function.

scholarly journals Palmitate-Induced MMP-9 Expression in the Human Monocytic Cells is Mediated through the TLR4-MyD88 Dependent Mechanism

2016 ◽  
Vol 39 (3) ◽  
pp. 889-900 ◽  
Author(s):  
Sardar Sindhu ◽  
Areej Al-Roub ◽  
Merin Koshy ◽  
Reeby Thomas ◽  
Rasheed Ahmad
Keyword(s):  
Underlying Mechanism ◽  
Positive Control ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Monocytic Cells ◽  
Metabolic Inflammation ◽  
Human Monocytic Cell Line ◽  
Tnf Α ◽  
Human Monocytic Cell

Background/Aims: Obese individuals are known to have increased Matrix metalloproteinase (MMP)-9 plasma levels and MMP-9 is reported to play an important role in obesity-associated adipose tissue inflammation. Since in obesity, the levels of circulatory saturated free fatty acid (FFA) palmitate (palimitic acid) are increased and modulate the expression of inflammatory mediators, the role of palmitate in the regulation of MMP-9 remains unclear. Methods: Human monocytic cell line THP-1 and primary monocytes were stimulated with palmitate and TNF-α (positive control). MMP-9 expression was assessed with real time RT-PCR and ELISA. Signaling pathways were studied by using THP-1-XBlue™ cells, THP-1-XBlue™-defMyD cells, anti-TLR4 mAb and TLR4 siRNA. Phosphorylation of NF-kB and c-Jun was analyzed by Western blotting. Results: Here, we provide the evidence that palmitate induces MMP-9 expression at both mRNA (THP-1: 6.8 ± 1.2 Fold; P = 0.01; Primary monocytes: 5.9 ± 0.7 Fold; P = 0.0003) and protein (THP1: 1116 ±14 pg/ml; P<0.001; Primary monocytes: 1426 ± 13.8; P = 0.0005) levels in human monocytic cells. Palmitate-induced MMP-9 secretion was markedly suppressed by neutralizing anti-TLR-4 antibody (P < 0.05). Furthermore, genetic silencing of TLR4 by siRNA also significantly abrogated the palmitate-induced up-regulation of MMP-9. Additionally, MyD88-/- THP-1 cells did not express MMP-9 in response to palmitate treatment. Increased NF-κB/AP-1 activity (P<0.05) was also observed in palmitate-treated THP-1 cells. Conclusion: Altogether, these results show that palmitate induces TLR4-dependent activation of MMP-9 gene expression, which requires the recruitment of MyD88 leading to activation of NF-kB/AP-1 transcription factors. Thus, our findings suggest that the palmitate-induced MMP-9 secretion might be an underlying mechanism of its increased levels in obesity and related metabolic inflammation.

scholarly journals Screening of compounds toxicity against human Monocytic cell line-THP-1 by flow cytometry

10.1251/bpo92 ◽  
2004 ◽  
Vol 6 (1) ◽  
pp. 220-225 ◽  
Author(s):  
Neora Pick ◽  
Scott Cameron ◽  
Dorit Arad ◽  
Yossef Av-Gay
Keyword(s):  
Flow Cytometry ◽  
Cell Line ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Human Monocytic Cell Line ◽  
Human Monocytic Cell

scholarly journals Modified Vaccinia Virus Ankara Triggers Chemotaxis of Monocytes and Early Respiratory Immigration of Leukocytes by Induction of CCL2 Expression

2009 ◽  
Vol 83 (6) ◽  
pp. 2540-2552 ◽  
Author(s):  
Michael H. Lehmann ◽  
Wolfgang Kastenmuller ◽  
Judith D. Kandemir ◽  
Florian Brandt ◽  
Yasemin Suezer ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Viral Vector ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Human Monocytic Cell Line ◽  
Modified Vaccinia Virus Ankara ◽  
Ccl2 Expression ◽  
Human Monocytic Cell

ABSTRACT Orthopoxviruses commonly enter into humans and animals via the respiratory tract. Herein, we show that immigration of leukocytes into the lung is triggered via intranasal infection of mice with modified vaccinia virus Ankara (MVA) and not with the vaccinia virus (VACV) Elstree, Wyeth, or Western Reserve (WR) strain. Immigrating cells were identified as monocytes, neutrophils, and CD4+ lymphocytes by flow cytometry and could be detected 24 h and 48 h postinfection. Using an in vitro chemotaxis assay, we confirmed that infection with MVA induces the expression of a soluble chemotactic factor for monocytes, identified as CCL2 (monocyte chemotactic protein-1 [MCP-1]). In contrast to infection with several other VACV strains, MVA induced the expression of CCL2, CCL3, CCL4, and CXCL10 in the human monocytic cell line THP-1 as well as in primary human monocytes. Thus, MVA, and not the VACV Elstree, Wyeth, or WR strain, consistently triggered the expression of a panel of chemokines, including CCL2, in the murine lung, correlating considerably with the immigration of leukocytes. Using CCL2-deficient mice, we demonstrate that CCL2 plays a key role in MVA-triggered respiratory immigration of leukocytes. Moreover, UV irradiation of MVA prevented CCL2 expression in vitro and in vivo as well as respiratory immigration of leukocytes, demonstrating the requirement for an activated molecular viral life cycle. We propose that MVA-triggered chemokine expression causes early immigration of leukocytes to the site of infection, a feature that is important for rapid immunization and its safety and efficiency as a viral vector.

scholarly journals Alkaline Comet Assay using the monocytic cell line THP-1

2019 ◽  
Author(s):  
Ana Neves-Costa ◽  
Dora Pedroso ◽  
Luis F Moita
Keyword(s):  
Comet Assay ◽  
Cell Line ◽  
Adherent Cell ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Strand Breaks ◽  
Human Monocytic Cell Line ◽  
Human Monocytic Cell ◽  
Dna Strand

Abstract This protocol details the experimental procedure for performing the comet assay, a very sensitive DNA break assay based on single cell gel electrophoresis.The analysis of DNA strand breaks, both single- and double-strand breaks (SSBs and DSBs, respectively), was performed in immune responsive cells. The cell line used was the human monocytic cell line THP-1, an adherent cell type with many known applications in in vitro studies of innate immunity. The comet assay is a robust procedure that allows the accurate and reproducible quantification of DNA damage. Here we describe not only the comet assay step-by-step protocol, but also some important aspects related to troubleshooting.

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