Trehalose, an mTOR independent autophagy inducer, alleviates human podocyte injury after puromycin aminonucleoside treatment

PLoS One. 2014 Nov 20;9(11):e113520. doi: 10.1371/journal.pone.0113520. eCollection 2014.

Abstract

Glomerular diseases are commonly characterized by podocyte injury including apoptosis, actin cytoskeleton rearrangement and detachment. However, the strategies for preventing podocyte damage remain insufficient. Recently autophagy has been regarded as a vital cytoprotective mechanism for keeping podocyte homeostasis. Thus, it is reasonable to utilize this mechanism to attenuate podocyte injury. Trehalose, a natural disaccharide, is an mTOR independent autophagy inducer. It is unclear whether trehalose alleviates podocyte injury. Therefore, we investigated the efficacy of trehalose in puromycin aminonucleoside (PAN)-treated podocytes which mimic cell damage in minimal change nephrotic syndrome in vitro. Human conditional immortalized podocytes were treated with trehalose with or without PAN. Autophagy was investigated by immunofluorescence staining for LC3 puncta and Western blotting for LC3, Atg5, p-AMPK, p-mTOR and its substrates. Podocyte apoptosis and necrosis were evaluated by flow cytometry and by measuring lactate dehydrogenase activity respectively. We also performed migration assay to examine podocyte recovery. It was shown that trehalose induced podocyte autophagy in an mTOR independent manner and without reactive oxygen species involvement. Podocyte apoptosis significantly decreased after trehalose treatment, while the inhibition of trehalose-induced autophagy abolished its protective effect. Additionally, the disrupted actin cytoskeleton of podocytes was partially reversed by trehalose, accompanying with less lamellipodias and diminished motility. These results suggested that trehalose induced autophagy in human podocytes and showed cytoprotective effects in PAN-treated podocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / drug effects
  • Antibiotics, Antineoplastic / pharmacology*
  • Apoptosis / drug effects
  • Autophagy / drug effects*
  • Autophagy-Related Protein 5
  • Blotting, Western
  • Cell Line
  • Cell Movement / drug effects
  • Humans
  • Microscopy, Fluorescence
  • Microtubule-Associated Proteins / immunology
  • Microtubule-Associated Proteins / metabolism
  • Nephrosis, Lipoid / metabolism
  • Nephrosis, Lipoid / pathology
  • Podocytes / cytology
  • Podocytes / drug effects
  • Podocytes / metabolism
  • Puromycin Aminonucleoside / pharmacology*
  • Reactive Oxygen Species / metabolism
  • TOR Serine-Threonine Kinases / metabolism*
  • Trehalose / pharmacology*

Substances

  • ATG5 protein, human
  • Antibiotics, Antineoplastic
  • Autophagy-Related Protein 5
  • MAP1LC3A protein, human
  • Microtubule-Associated Proteins
  • Reactive Oxygen Species
  • Puromycin Aminonucleoside
  • Trehalose
  • MTOR protein, human
  • TOR Serine-Threonine Kinases

Grants and funding

This work was partially supported by grants to HWL (i) Competitive Research Grants for Newly Recruited Junior Academic Staff (NRJS-A-PM13); (ii) Departmental Research Fund, The Hong Kong Polytechnic University and (iii) Early Career Scheme from Research Grants Council of the Hong Kong Special Administrative Region, China (RGC#589413). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.