Related Experiment Video

Updated: Jun 10, 2026

Bone Marrow-derived Macrophage Production
07:06

Bone Marrow-derived Macrophage Production

Published on: November 22, 2013

ß-adrenergic stimulation increases macrophage CD14 expression and E. coli phagocytosis through PKA signaling

Kuzhali Muthu1, Li-K He, Andrea Szilagyi

  • 1Department of Surgery, Loyola University Medical Center, Maywood, IL 60153, USA. kmuthu@lumc.edu

Journal of Leukocyte Biology
|July 21, 2010
PubMed

Insights

Beta-adrenergic stimulation, like with isoproterenol, boosts CD14 expression and bacterial phagocytosis in mouse bone marrow macrophages (BMØ). This pathway involves cAMP-dependent PKA, highlighting potential therapeutic roles for beta-adrenergic agents in innate immunity.

Area of Science:

  • Immunology
  • Cell Biology
  • Pharmacology

Background:

  • CD14 glycoprotein binds bacterial lipopolysaccharide (LPS) in macrophages (MØ), crucial for innate immunity.
  • Elevated catecholamine (CA) levels during critical injury and sepsis impact MØ inflammatory functions.
  • The role of beta-adrenergic stimulation on CD14 expression and phagocytosis in MØ remains unclear.

Purpose of the Study:

  • To investigate the hypothesis that beta-adrenergic stimulation regulates CD14 expression and bacterial phagocytosis in mouse bone marrow macrophages (BMØ).

Main Methods:

  • Murine BMØ were stimulated with isoproterenol.
  • Inhibitor studies using H-89 (PKA inhibitor) and gene-silencing (siRNA) were performed.
  • Bacterial phagocytosis was assessed using live Escherichia coli uptake.
  • Experiments utilized CD14-deficient (CD14(-/-)) mice.

Main Results:

  • Isoproterenol induced a dose-dependent increase in cell surface CD14 expression in BMØ.
  • The response was mediated by cAMP-dependent protein kinase A (PKA).
  • Increased CD14 expression correlated with enhanced E. coli uptake, dependent on CD14.
  • Isoproterenol-mediated phagocytosis and CD14 expression shared similar EC50 values.

Conclusions:

  • Beta-adrenergic stimulation significantly increases CD14 expression and bacterial phagocytosis in BMØ.
  • This effect is mediated by a common signaling pathway involving cAMP-dependent PKA.
  • Beta-adrenergic agents may represent a potential therapeutic strategy to modulate innate immune functions.

More Related Videos

Isolation Protocol of Mouse Monocyte-derived Dendritic Cells and Their Subsequent In Vitro Activation with Tumor Immune Complexes11:48

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

Published on: May 31, 2018

A Macrophage Reporter Cell Assay to Examine Toll-Like Receptor-Mediated NF-kB/AP-1 Signaling on Adsorbed Protein Layers on Polymeric Surfaces07:55

A Macrophage Reporter Cell Assay to Examine Toll-Like Receptor-Mediated NF-kB/AP-1 Signaling on Adsorbed Protein Layers on Polymeric Surfaces

Published on: January 7, 2020

Related Concept Videos

GPCRs Regulate Adenylyl Cylase Activity01:09

GPCRs Regulate Adenylyl Cylase Activity

Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of cells.
Two...
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...
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,...
Adrenergic Receptors: β Subtype01:26

Adrenergic Receptors: β Subtype

β-adrenoceptors have varied sensitivities towards adrenaline, noradrenaline, and isoprenaline. The order of agonist potency is as follows:
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Defense Against Bacterial Pathogens01:31

Defense Against Bacterial Pathogens

The human immune system is a complex network of cells, tissues, and organs that work together to defend the body against bacterial infections. It consists of various immune cells, each playing a specific role in the defense mechanism.
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
Immune Surveillance by NK Cells and Phagocytes01:25

Immune Surveillance by NK Cells and Phagocytes

Immune surveillance is an integral part of the innate immune system, involving the continuous monitoring of peripheral tissues to detect and respond to pathogens, infected cells, or cancerous cells. This surveillance is conducted primarily by natural killer (NK) cells and phagocytes, which employ distinct but complementary mechanisms to identify and eliminate threats.
Natural Killer Cells: The Fast Responders
NK cells are large granular lymphocytes found in the blood and lymphatic system. These...