Related Experiment Video

Updated: Jan 27, 2026

Production and Detection of Reactive Oxygen Species ROS in Cancers
07:17

Production and Detection of Reactive Oxygen Species ROS in Cancers

Published on: November 21, 2011

71.0K

Vibrio cholerae OmpU Mediates CD36-Dependent Reactive Oxygen Species Generation Triggering an Additional Pathway of

G V R Krishna Prasad1, Vinica Dhar1, Arunika Mukhopadhaya2

  • 1Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, 140306 Punjab, India.

Journal of Immunology (Baltimore, Md. : 1950)
|March 15, 2019
PubMed

Insights

Vibrio cholerae porin OmpU triggers inflammatory responses via TLR2 and CD36 receptors. Macrophages use both, while monocytes rely solely on TLR2, explaining macrophages

Area of Science:

  • Immunology
  • Microbiology
  • Cell Biology

Background:

  • OmpU is a porin from Gram-negative bacteria Vibrio cholerae.
  • OmpU is known to induce inflammatory cytokine production in human and mouse monocytes and macrophages via TLR1/2-MyD88-NF-κB signaling.

Purpose of the Study:

  • To investigate the mechanisms underlying OmpU-induced inflammatory responses in monocytes and macrophages.
  • To identify the specific signaling pathways and receptors involved in OmpU recognition.

Main Methods:

  • Cell culture of human and mouse monocytes and macrophages.
  • Stimulation with purified OmpU protein.
  • Analysis of MAPK (p38, JNK) activation.
  • Assessment of reactive oxygen species (ROS) generation.
  • Investigation of Toll-like receptor 2 (TLR2) and CD36 involvement.
  • Confocal microscopy for OmpU translocation studies.

Main Results:

  • OmpU induces p38 and JNK MAPK activation in both monocytes and macrophages.
  • In macrophages, p38 activation is TLR2-dependent, while JNK activation involves ROS from NADPH oxidase and mitochondria.
  • OmpU-mediated mitochondrial ROS may involve OmpU translocation to mitochondria.
  • NADPH oxidase-mediated ROS production is linked to CD36 activation, identifying OmpU as a novel CD36 ligand.
  • In monocytes, both JNK and p38 activation are solely TLR2-dependent.

Conclusions:

  • Macrophages utilize both TLR2 and CD36 to recognize OmpU, leading to potent proinflammatory responses.
  • Monocytes primarily rely on TLR2 for OmpU recognition.
  • The differential receptor usage by macrophages and monocytes contributes to the heightened inflammatory capacity of macrophages.

More Related Videos

In Vivo Imaging of Reactive Oxygen Species in a Murine Wound Model06:40

In Vivo Imaging of Reactive Oxygen Species in a Murine Wound Model

Published on: November 17, 2018

11.7K
Detecting, Visualizing and Quantitating the Generation of Reactive Oxygen Species in an Amoeba Model System16:41

Detecting, Visualizing and Quantitating the Generation of Reactive Oxygen Species in an Amoeba Model System

Published on: November 5, 2013

16.6K

Related Concept Videos

NF-κB-dependent Signaling Pathway02:26

NF-κB-dependent Signaling Pathway

The transcription factor NF-κB was discovered in 1986 in the lab of Nobel laureate Professor David Baltimore, for its interaction with the immunoglobulin light chain enhancer in B-cells. After more than three decades of study, it is now evident that NF-κB regulates the expression of over 100 genes. Most of these genes play an essential role in the innate and adaptive immune responses as well as the inflammatory responses of animals.
NF-κB-dependent Signaling Mechanism
The...
10.0K
cAMP-dependent Protein Kinase Pathways01:25

cAMP-dependent Protein Kinase Pathways

Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
8.4K
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
8.2K
What is a Species?01:17

What is a Species?

Overview
49.7K
Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)01:27

Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)

α,β-Unsaturated carbonyl compounds with two electrophilic sites, the carbonyl carbon, and the β carbon, are susceptible to nucleophilic attack via two modes: conjugate or 1,4-addition and direct or 1,2-addition.
Conjugate addition results in a thermodynamically stable product. The reaction retains the stronger C=O bond at the expense of the weaker C=C π bond. The process is slow as the β carbon is less electrophilic than the carbonyl carbon.
Direct addition products are...
4.3K
C4 Pathway and CAM01:27

C4 Pathway and CAM

Most plants use the C3 pathway for carbon fixation. However, some plants, such as sugar cane, corn, and cacti that grow in hot conditions, use alternative pathways to fix carbon and conserve energy loss due to photorespiration. Photorespiration is the process that occurs when the oxygen concentration is high. Under such conditions, the rubisco enzyme in the Calvin cycle binds O2 instead of CO2, which halts photosynthesis and consumes energy.
C4 Pathway
The C4 pathway is used by plants such as...
49.1K