Expression of CPI-17 in smooth muscle during embryonic development and in neointimal lesion formation

Histochem Cell Biol. 2009 Aug;132(2):191-8. doi: 10.1007/s00418-009-0604-2. Epub 2009 May 13.

Abstract

Ca(2+) sensitivity of smooth muscle (SM) contraction is determined by CPI-17, an inhibitor protein for myosin light chain phosphatase (MLCP). CPI-17 is highly expressed in mature SM cells, but the expression level varies under pathological conditions. Here, we determined the expression of CPI-17 in embryonic SM tissues and arterial neointimal lesions using immunohistochemistry. As seen in adult animals, the predominant expression of CPI-17 was detected at SM tissues on mouse embryonic sections, whereas MLCP was ubiquitously expressed. Compared with SM alpha-actin, CPI-17 expression doubled in arterial SM from embryonic day E10 to E14. Like SM alpha-actin and other SM marker proteins, CPI-17 was expressed in embryonic heart, and the expression was down-regulated at E17. In adult rat, CPI-17 expression level was reduced to 30% in the neointima of injured rat aorta, compared with the SM layers, whereas the expression of MLCP was unchanged in both regions. Unlike other SM proteins, CPI-17 was detected at non-SM organs in the mouse embryo, such as embryonic neurons and epithelium. Thus, CPI-17 expression is reversibly controlled in response to the phenotype transition of SM cells that restricts the signal to differentiated SM cells and particular cell types.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aorta / enzymology*
  • Aorta / injuries
  • Embryonic Development*
  • Immunohistochemistry
  • Intracellular Signaling Peptides and Proteins
  • Mice
  • Muscle Proteins / analysis
  • Muscle Proteins / biosynthesis*
  • Muscle, Smooth / embryology
  • Muscle, Smooth / enzymology*
  • Myocardium / enzymology
  • Phosphoproteins / analysis
  • Phosphoproteins / biosynthesis*
  • Rats
  • Rats, Sprague-Dawley
  • Tunica Intima / enzymology*
  • Tunica Intima / injuries

Substances

  • Intracellular Signaling Peptides and Proteins
  • Muscle Proteins
  • Phosphoproteins
  • Ppp1r14a protein, mouse
  • Ppp1r14a protein, rat