Tacrolimus Protects Podocytes from Injury in Lupus Nephritis Partly by Stabilizing the Cytoskeleton and Inhibiting Podocyte Apoptosis

PLoS One. 2015 Jul 10;10(7):e0132724. doi: 10.1371/journal.pone.0132724. eCollection 2015.

Abstract

Objective: Several studies have reported that tacrolimus (TAC) significantly reduced proteinuria in lupus nephritis (LN) patients and mouse models. However, the mechanism for this effect remains undetermined. This study explored the mechanism of how TAC protects podocytes from injury to identify new targets for protecting renal function.

Methods: MRL/lpr mice were given TAC at a dosage of 0.1 mg/kg per day by intragastric administration for 8 weeks. Urine and blood samples were collected. Kidney sections (2 μm) were stained with hematoxylin-eosin (HE), periodic acid-Schiff base (PAS) and Masson's trichrome stain. Mouse podocyte cells (MPC5) were treated with TAC and/or TGF-β1 for 48 h. The mRNA levels and protein expression of synaptopodin and Wilms' tumor 1 (WT1) were determined by real-time PCR, Western blotting and/or immunofluorescence, respectively. Flow cytometry was used to detect cell apoptosis with annexin V. Podocyte foot processes were observed under transmission electron microscopy. IgG and C3 deposition were assessed with immunofluorescence assays and confocal microscopy.

Results: Synaptopodin expression significantly decreased in MRL/lpr disease control mice, accompanied by increases in 24-h proteinuria, blood urea nitrogen, and serum creatinine. TAC, however, reduced proteinuria, improved renal function, attenuated renal pathology, restored synaptopodin expression and preserved podocyte numbers. In MPC5 cells, TGF-β1 enhanced F-actin damage in podocytes and TAC stabilized it. TAC also decreased TGF-β1-induced podocyte apoptosis in vitro and inhibited foot process fusion in MRL/lpr mice. In addition, our results also showed TAC inhibited glomerular deposition of IgG and C3.

Conclusion: This study demonstrated that TAC reduced proteinuria and preserved renal function in LN through protecting podocytes from injury partly by stabilizing podocyte actin cytoskeleton and inhibiting podocyte apoptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis*
  • Cell Line
  • Complement C3 / metabolism
  • Cytoprotection
  • Cytoskeleton / drug effects
  • Cytoskeleton / pathology*
  • Drug Evaluation, Preclinical
  • Female
  • Immunoglobulin G / metabolism
  • Immunosuppressive Agents / pharmacology
  • Immunosuppressive Agents / therapeutic use
  • Kidney / drug effects
  • Kidney / pathology
  • Kidney / physiopathology
  • Lupus Nephritis / drug therapy*
  • Lupus Nephritis / metabolism
  • Lupus Nephritis / pathology
  • Mice, Inbred MRL lpr
  • Microfilament Proteins / metabolism
  • Podocytes / drug effects
  • Podocytes / physiology*
  • Protein Stability
  • Proteinuria / drug therapy
  • Proteinuria / metabolism
  • Tacrolimus / pharmacokinetics*
  • Tacrolimus / therapeutic use

Substances

  • Complement C3
  • Immunoglobulin G
  • Immunosuppressive Agents
  • Microfilament Proteins
  • Synpo protein, mouse
  • Tacrolimus

Grant support

This work was supported by grants from National Key Technology Research and Development Program of the Ministry of Science and Technology, China (No. 2011BAI10B05), Department of Science and Technology, Guangzhou City, China (No. 2010U1-E00831), and 5010 clinical Program of Sun Yat-sen University (No. 2007007) to Xueqing Yu. Qinghua Liu was supported by grants from National Natural Science Foundation of China (No. 81370863), The Fundamental Research Funds for the Central Universities (No. 13YKPY17), Research Fund for PhD Program, Ministry of Education, China (No. 20100171120067) and Natural Science Foundation of Guangdong Province (No. 10451008901005957). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Astellas Pharmaceuticals supplied the tacrolimus used in this study, but it played no role in the design and conduct of this study as well as in the analysis and the interpretation of results. Writing and publication of the manuscript were not contingent on the approval of Astellas Pharmaceuticals.