Related Experiment Video

Updated: Jul 2, 2026

Isolation Protocol of Mouse Monocyte-derived Dendritic Cells and Their Subsequent In Vitro Activation with Tumor Immune Complexes
11:48

Isolation Protocol of Mouse Monocyte-derived Dendritic Cells and Their Subsequent In Vitro Activation with Tumor Immune Complexes

Published on: May 31, 2018

Immunomodulated signaling in macrophages: Studies on activation of Raf-1, MAPK, cPLA(2) and secretion of IL-12

Z Zhang1, Q Song, M Lin

  • 1Shanghai Institute of Cell Biology, Chinese Academy of Sciences, China.

Science in China. Series C, Life Sciences
|August 30, 2008
PubMed

Insights

Lipopolysaccharide (LPS) modulates immune cells by activating signaling pathways. This study reveals connections between protein kinase C (PKC) and Raf-1/MAPK pathways, influencing interleukin-12 (IL-12) secretion in macrophages.

Area of Science:

  • Immunology
  • Cell Signaling
  • Molecular Biology

Background:

  • The precise mechanisms of lipopolysaccharide (LPS)-mediated immunomodulation in murine peritoneal macrophages remain largely unelucidated.
  • Understanding signal transduction pathways is crucial for comprehending macrophage responses to immune stimuli like LPS.

Purpose of the Study:

  • To investigate the signal transduction pathways involved in LPS-mediated immunomodulation of murine peritoneal macrophages.
  • To explore the relationship between protein kinase C (PKC) signaling and the Raf-1/Mitogen-Activated Protein Kinase (MAPK) pathway in this context.

Main Methods:

  • Activation and phosphorylation of key signaling molecules including Ras, Raf-1, MAPK p44, and MAPK p42 were assessed.
  • Activation of cytosolic phospholipase A2 (cPLA(2)) and the release of arachidonic acid (AA) were measured.
  • The activation and translocation of PKC-alpha and PKC-epsilon in response to LPS and phorbol 12-myristate 13-acetate (PMA) were examined.

Main Results:

  • LPS and PMA treatment led to the phosphorylation of downstream signal molecules of Ras, including Raf-1, MAPK p44, and MAPK p42.
  • cPLA(2) was activated, resulting in a significant increase in the release of [3H] arachidonic acid (AA) from macrophages.
  • LPS and PMA were found to trigger the activation and translocation of PKC-alpha and PKC-epsilon.

Conclusions:

  • A connection exists between the PKC signaling pathway and the Raf-1/MAPK pathway in LPS-stimulated macrophages.
  • The activation of these signaling pathways is closely linked to the secretion of interleukin-12 (IL-12) during LPS-induced macrophage modulation.

More Related Videos

Reprograming Model of Human Monocyte-derived Macrophages for In-vitro Assays08:37

Reprograming Model of Human Monocyte-derived Macrophages for In-vitro Assays

Published on: April 18, 2025

Related Concept Videos

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...
The JAK-STAT Signaling Pathway01:20

The JAK-STAT Signaling Pathway

Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as  SH2...
T Cell Types and Functions01:24

T Cell Types and Functions

When T cells with CD4 markers are activated, they give rise to two types of effector cells: helper T cells and regulatory T cells. Meanwhile, T cells with CD8 markers differentiate into effector cytotoxic T cells. The differentiation of CD4 T cells into helper T cell subsets, such as Th1, Th2, and Th17 cells, is dependent on the antigen type, antigen-presenting cell, and regulatory cytokines.
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
Interactions Between Signaling Pathways01:19

Interactions Between Signaling Pathways

Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...