Related Experiment Video

Updated: Apr 1, 2026

Determination of Tolerable Fatty Acids and Cholera Toxin Concentrations Using Human Intestinal Epithelial Cells and BALB/c Mouse Macrophages
09:39

Determination of Tolerable Fatty Acids and Cholera Toxin Concentrations Using Human Intestinal Epithelial Cells and BALB/c Mouse Macrophages

Published on: May 30, 2013

10.6K

Vibrio cholerae porin OmpU induces LPS tolerance by attenuating TLR-mediated signaling

Sanica C Sakharwade1, Arunika Mukhopadhaya1

  • 1Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Manauli, 140306 Punjab, India.

Molecular Immunology
|October 12, 2015
PubMed

Insights

Vibrio cholerae OmpU porin suppresses lipopolysaccharide (LPS)-mediated immune responses by attenuating Toll-like receptor (TLR) signaling. OmpU pretreatment inhibits pro-inflammatory cytokine production and enhances macrophage phagocytosis.

Area of Science:

  • Immunology
  • Microbiology
  • Molecular Biology

Background:

  • Porins, like Vibrio cholerae OmpU, are pathogen-associated molecular patterns recognized by the host immune system.
  • V. cholerae OmpU enhances bacterial survival but exhibits complex immunomodulatory effects, including both pro-inflammatory and anti-inflammatory actions.

Purpose of the Study:

  • To investigate the impact of OmpU pretreatment on lipopolysaccharide (LPS)-mediated immune responses.
  • To elucidate the molecular mechanisms by which OmpU modulates Toll-like receptor (TLR) signaling pathways.

Main Methods:

  • Treatment of RAW 264.7 mouse macrophage cells and human peripheral blood mononuclear cells (PBMCs) with OmpU followed by LPS stimulation.
  • Analysis of M2 polarization, TLR2/TLR6 signaling, MyD88 and IRAK recruitment, NFκB translocation, IRAK-M expression, IL-10 production, TNFα levels, phagocytosis, and co-stimulatory molecule expression.

Main Results:

  • OmpU pretreatment did not induce M2 polarization of macrophages/monocytes.
  • OmpU attenuated LPS-mediated TLR2/TLR6 signaling by reducing TLR-MyD88-IRAK complex formation and NFκB nuclear translocation.
  • OmpU upregulated IRAK-M expression, partially involved IL-10 in down-regulating LPS-induced TNFα production, enhanced phagocytosis, and reduced co-stimulatory molecule expression.

Conclusions:

  • OmpU suppresses LPS-mediated immune responses by attenuating the TLR signaling pathway.
  • OmpU exhibits immunomodulatory functions impacting macrophage polarization, cytokine production, and phagocytic activity.
Keywords:
Down-regulationMacrophage functionOmpUPorinVibrio cholerae

More Related Videos

Coincubation Assay for Quantifying Competitive Interactions between Vibrio fischeri Isolates07:43

Coincubation Assay for Quantifying Competitive Interactions between Vibrio fischeri Isolates

Published on: July 22, 2019

8.8K
Laboratory Techniques Used to Maintain and Differentiate Biotypes of Vibrio cholerae Clinical and Environmental Isolates07:58

Laboratory Techniques Used to Maintain and Differentiate Biotypes of Vibrio cholerae Clinical and Environmental Isolates

Published on: May 30, 2017

11.6K

Related Concept Videos

Cholera01:25

Cholera

Cholera is an acute gastrointestinal disease caused by the Gram-negative bacterium Vibrio cholerae. It is transmitted primarily via the fecal-oral route through the ingestion of contaminated water or food.Vibrio cholerae is a motile, Gram-negative bacterium of the family Vibrionaceae, primarily associated with waterborne outbreaks in areas with inadequate sanitation. Although over 200 serogroups of V. cholerae exist, only O1 and O139 are responsible for epidemic cholera. The O1 serogroup,...
44
Regulation of Bacterial Virulence01:28

Regulation of Bacterial Virulence

Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
36
Formation of Lipopolysaccharides01:19

Formation of Lipopolysaccharides

Lipopolysaccharides (LPS) are crucial components of the outer membrane of Gram-negative bacteria, serving both structural and functional roles. It contributes to membrane stability and protects bacteria from host immune responses. LPS is composed of three major regions—lipid A, a core oligosaccharide, and an O antigen. The biosynthesis and assembly of LPS involve a highly coordinated set of enzymatic reactions and transport mechanisms. Additionally, LPS is recognized as an endotoxin,...
945
Stringent Response in E. coli01:23

Stringent Response in E. coli

Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
468
Bacterial Signaling01:30

Bacterial Signaling

Bacterial signaling can occur within bacteria (intracellular) or between bacteria (intercellular). At times, a group of bacteria behaves like a community. To achieve this, they engage in quorum sensing, the perception of higher cell density that causes changes in gene expression. Quorum sensing involves both extracellular and intracellular signaling. The signaling cascade starts with a molecule called an autoinducer (AI). Individual bacteria produce AIs that move out of the bacterial cell...
43.2K
Bacterial Translocation and Protein Secretion01:26

Bacterial Translocation and Protein Secretion

Bacterial protein secretion involves translocation systems to ensure proteins reach their designated locations, including the plasma membrane, periplasm, outer membrane, or the external environment. These translocation systems are vital for bacterial physiology, supporting processes like membrane assembly, enzymatic activity in the periplasm, and interactions with the external environment. The division of labor between Sec and Tat pathways ensures efficiency in handling proteins with diverse...
994