Immunomodulatory effects of chicken cathelicidin-2 on a primary hepatic cell co-culture model

PLoS One. 2022 Oct 10;17(10):e0275847. doi: 10.1371/journal.pone.0275847. eCollection 2022.

Abstract

Cathelicidin-2 is an antimicrobial peptide (AMP) produced as part of the innate immune system of chickens and might be a new candidate to combat infection and inflammation within the gut-liver axis. Studying the hepatic immune response is of high importance as the liver is primarily exposed to gut-derived pathogen-associated molecular patterns. The aim of the present study was to assess the effects of chicken cathelicidin-2 alone or combined with lipoteichoic acid (LTA) or phorbol myristate acetate (PMA) on cell viability, immune response and redox homeostasis in a primary hepatocyte-non-parenchymal cell co-culture of chicken origin. Both concentrations of cathelicidin-2 decreased the cellular metabolic activity and increased the extracellular lactate dehydrogenase (LDH) activity reflecting reduced membrane integrity. Neither LTA nor PMA affected these parameters, and when combined with LTA, cathelicidin-2 could not influence the LDH activity. Cathelicidin-2 had an increasing effect on the concentration of the proinflammatory CXCLi2 and interferon- (IFN-)γ, and on that of the anti-inflammatory IL-10. Meanwhile, macrophage colony stimulating factor (M-CSF), playing a complex role in inflammation, was diminished by the AMP. LTA elevated IFN-γ and decreased M-CSF levels, while PMA only increased the concentration of M-CSF. Both concentrations of cathelicidin-2 increased the H2O2 release of the cells, but the concentration of malondialdehyde as a lipid peroxidation marker was not affected. Our findings give evidence that cathelicidin-2 can also possess anti-inflammatory effects, reflected by the alleviation of the LTA-triggered IFN-γ elevation, and by reducing the M-CSF production induced by PMA. Based on the present results, cathelicidin-2 plays a substantial role in modulating the hepatic immune response with a multifaceted mode of action. It was found to have dose-dependent effects on metabolic activity, membrane integrity, and reactive oxygen species production, indicating that using it in excessively high concentrations can contribute to cell damage. In conclusion, cathelicidin-2 seems to be a promising candidate for future immunomodulating drug development with an attempt to reduce the application of antibiotics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Monophosphate
  • Animals
  • Anti-Bacterial Agents
  • Anti-Inflammatory Agents / pharmacology
  • Antimicrobial Cationic Peptides
  • Cathelicidins
  • Chickens*
  • Coculture Techniques
  • Hepatocytes
  • Hydrogen Peroxide
  • Immunity
  • Inflammation
  • Interferon-gamma
  • Interleukin-10
  • Lactate Dehydrogenases
  • Liver
  • Macrophage Colony-Stimulating Factor*
  • Malondialdehyde
  • Pathogen-Associated Molecular Pattern Molecules
  • Reactive Oxygen Species
  • Tetradecanoylphorbol Acetate

Substances

  • Anti-Bacterial Agents
  • Anti-Inflammatory Agents
  • Antimicrobial Cationic Peptides
  • Pathogen-Associated Molecular Pattern Molecules
  • Reactive Oxygen Species
  • Interleukin-10
  • Adenosine Monophosphate
  • Malondialdehyde
  • Macrophage Colony-Stimulating Factor
  • Interferon-gamma
  • Hydrogen Peroxide
  • Lactate Dehydrogenases
  • Tetradecanoylphorbol Acetate
  • Cathelicidins

Grants and funding

The work was supported by the Hungarian National Research, Development and Innovation Office [grant numbers OTKA FK 134940; TKP2020-NKA-01 financed under the 2020-4.1.1-TKP2020 funding scheme, G.M. received the fundings]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.