Renal cells express different forms of vimentin: the independent expression alteration of these forms is important in cell resistance to osmotic stress and apoptosis

PLoS One. 2013 Jul 11;8(7):e68301. doi: 10.1371/journal.pone.0068301. Print 2013.

Abstract

Osmotic stress has been shown to regulate cytoskeletal protein expression. It is generally known that vimentin is rapidly degraded during apoptosis by multiple caspases, resulting in diverse vimentin fragments. Despite the existence of the known apoptotic vimentin fragments, we demonstrated in our study the existence of different forms of vimentin VIM I, II, III, and IV with different molecular weights in various renal cell lines. Using a proteomics approach followed by western blot analyses and immunofluorescence staining, we proved the apoptosis-independent existence and differential regulation of different vimentin forms under varying conditions of osmolarity in renal cells. Similar impacts of osmotic stress were also observed on the expression of other cytoskeleton intermediate filament proteins; e.g., cytokeratin. Interestingly, 2D western blot analysis revealed that the forms of vimentin are regulated independently of each other under glucose and NaCl osmotic stress. Renal cells, adapted to high NaCl osmotic stress, express a high level of VIM IV (the form with the highest molecular weight), besides the three other forms, and exhibit higher resistance to apoptotic induction with TNF-α or staurosporin compared to the control. In contrast, renal cells that are adapted to high glucose concentration and express only the lower-molecular-weight forms VIM I and II, were more susceptible to apoptosis. Our data proved the existence of different vimentin forms, which play an important role in cell resistance to osmotic stress and are involved in cell protection against apoptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / physiology*
  • Cell Survival / genetics
  • Cytoskeleton / genetics
  • Cytoskeleton / metabolism
  • Epithelial Cells / metabolism
  • Fibroblasts / metabolism
  • Glucose / metabolism
  • Humans
  • Intermediate Filament Proteins / genetics
  • Intermediate Filament Proteins / metabolism
  • Intermediate Filaments / genetics
  • Intermediate Filaments / metabolism
  • Kidney / metabolism*
  • Molecular Weight
  • Osmotic Pressure
  • Proteome / genetics
  • Proteome / metabolism
  • Proteomics / methods
  • Rabbits
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / metabolism
  • Vimentin / metabolism*

Substances

  • Intermediate Filament Proteins
  • Proteome
  • Tumor Necrosis Factor-alpha
  • Vimentin
  • Glucose

Grants and funding

We acknowledge support by the German Research Foundation and the Open Access Publication Funds of the Göttingen University. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.