Short-Chain Fatty Acids Restore Glomerular Endothelial Cell Stabilization After Exposure to Type 2 Diabetes Mellitus (T2DM) Serum, Circumventing the Reduced CPT1A Transporter

Journal of the American Society of Nephrology, vol. 34, pp. 495

Abstract

Background: Renal injury is one of the major consequences for patients with type 2 diabetes mellitus (T2DM). Previously, we observed that diabetic nephropathy (DN) resulted in loss of the endothelial glycocalyx, but the molecular and metabolic mechanisms underlying this loss and in general endothelial dysfunction in T2DM remain largely unexplained. In the present study we tested the mechanistic and metabolic changes in human primary glomerular endothelial cells (huGEnCs) exposed to serum from patients with T2DM. Methods: HuGenCs have been exposed for 4 days to T2DM serum in either static or laminar flow conditions. Cells were then used for seahorse and ECIS assays, to measure mitochondrial function and monolayer integrity, respectively. In order to visualize the monolayer, cells were stained for VE-cadherin and β-catenin. We also ran qPCR analysis to check the expression levels of endothelial and metabolic genes. Results: qPCR data showed that huGenCs cultured with T2DM serum have an increased IL-8 mRNA expression while HAS2, HAS3, NOS3 and the fatty acid transporter CPT1A mRNA were reduced. For this reason, we performed a CPT1A knockdown to investigate the effect of the lack of this transporter in huGenCs. Monolayer resistance, either in the presence of T2DM serum or after CPT1A knockdown, was decreased. In each case, administration of the short chain fatty acids (SCFAs) butyrate and acetate restored barrier function. The beneficial effects of SCFAs on the endothelial monolayer were also confirmed when visualizing cell-cell contacts with immunofluorescence staining's for VE-cadherin and β-catenin. Using seahorse assay, we observed that SCFAs also improved fatty acid oxidation which was reduced after T2DM serum exposure. Conclusions: SCFAs supplementation can rescue endothelial cell integrity after treatment with T2DM serum. Mechanistically, reduction of CPT1A in ECs exposed to T2DM serum revealed the importance of fatty acids for ECs homeostasis, which was confirmed by the knockdown of CPT1A. With butyrate and acetate supplementation we can circumvent this pathway and restore cellular homeostasis by improving fatty acids metabolism.

Authors 6

1. Maria Novella Nicese Aachen

   Leiden University Medical Center

   Affiliation as printed

   Leids Universitair Medisch Centrum, Leiden, Netherlands

2. Lushun Yuan Aachen

   Leiden University Medical Center

   Affiliation as printed

   Leids Universitair Medisch Centrum, Leiden, Netherlands

3. Gangqi Wang Aachen

   Leiden University Medical Center

   Affiliation as printed

   Leids Universitair Medisch Centrum, Leiden, Netherlands

4. Ton J. Rabelink Aachen

   Leiden University Medical Center

   Affiliation as printed

   Leids Universitair Medisch Centrum, Leiden, Netherlands

5. Joris I. Rotmans Aachen

   Leiden University Medical Center

   Affiliation as printed

   Leids Universitair Medisch Centrum, Leiden, Netherlands

6. Bernard M. van den Berg Aachen

   Leiden University Medical Center

   Affiliation as printed

   Leids Universitair Medisch Centrum, Leiden, Netherlands