Abstract: SA-PO941
Protein Kinase C-Beta Deficiency and Inhibition Exacerbate High Glucose-Induced Peritoneal Damage via M1/M2 Macrophage Polarization
Session Information
- Dialysis: Peritoneal Dialysis - III
October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Dialysis
- 703 Dialysis: Peritoneal Dialysis
Authors
- Balzer, Michael S., Hannover Medical School, Hannover, Germany
- Helmke, Alexandra, Hannover Medical School, Hannover, Germany
- Rong, Song, Hannover Medical School, Hannover, Germany
- Von Vietinghoff, Sibylle, Hannover Medical School, Hannover, Germany
- Haller, Hermann G., Hannover Medical School, Hannover, Germany
- Shushakova, Nelli, Hannover Medical School, Hannover, Germany
Background
Macrophage (MØ)-driven inflammation is a key hallmark of glucose-mediated damage to the peritoneal membrane (PM) during peritoneal dialysis. We have recently shown that in mesothelium PKCα is a major mediator of PM damage, whereas PKCβ deficiency results in increased glucose-mediated PM damage. PKCβ is expressed most abundantly in MØ. We hypothesized that within a high glucose milieu PKCβ plays an important role in controlling MØ activation and function.
Methods
Combining qPCR, ELISA, Western blot, and flow cytometry we investigated primary murine peritoneal MØ of PKCβ-/- and wild type (WT) mice, murine bone marrow-derived MØ of WT mice, and primary human peripheral blood monocyte-derived MØ during normal (10mM) and high glucose (120mM) conditions. Some experiments involved LPS stimulation and pharmacological PKCβ inhibition using ruboxistaurin. In vivo PM damage was evaluated in a chronic peritoneal dialysis mouse model in PKCβ-/- and WT mice using flow cytometry and immunofluorescence.
Results
In vitro murine MØ, in comparison to PKCα, abundantly (>50-fold) expressed PKCβ mRNA at normal glucose conditions. A high glucose milieu induced PKCβ and suppressed PKCα mRNA and protein expression. High glucose conditions facilitated murine and human MØ polarization towards M2. Both genetic deficiency and pharmacological inhibition of PKCβ increased high glucose+LPS-mediated IL-6, TNFα, and MCP-1 production and decreased IL-10 release compared to a state of genetic or functional presence of PKCβ.
In vivo catheter-delivered treatment with high glucose peritoneal dialysis fluid for 5 weeks induced PKCβ up-regulation in omentum rich of MØ in WT mice and resulted in an inflammatory response and PM damage characterized by fibrosis and neo-angiogenesis. In comparison to WT mice, destructive changes were strongly aggravated in PKCβ-/- animals. Finally, flow cytometry and immunofluorescence demonstrated a substantial M1 polarization of peritoneal MØ in PKCβ-/- mice, while WT mice predominantly mounted an M2 response.
Conclusion
PKCβ is the dominant PKC isoform in peritoneal macrophages. It is up-regulated and exerts peritoneal anti-inflammatory effects in a high glucose milieu both in vitro and in an in vivo mouse model of chronic peritoneal dialysis via M1/M2 macrophage polarization.
Funding
- Government Support - Non-U.S.