Sympathetic neurons express and secrete MMP-2 and MT1-MMP to control nerve sprouting via pro-NGF conversion

Cell Mol Neurobiol. 2011 Jan;31(1):17-25. doi: 10.1007/s10571-010-9548-2. Epub 2010 Aug 4.

Abstract

Recently, we have shown that high frequency electrical field stimulation (HFES) of sympathetic neurons (SN) induces nerve sprouting by up-regulation of nerve growth factor (NGF) which targets the tyrosine kinase A receptor (TrkA) in an autocrine/paracrine manner. There is increasing evidence that matrix metalloproteinase-2 (MMP-2) is not only involved in extracellular matrix (ECM) turnover but may also exert beneficial effects during neuronal growth. Therefore, this study aimed to investigate the regulation and function of MMP-2 and its major activator membrane type 1-matrix metalloproteinase (MT1-MMP) as well its inhibitor TIMP-1 in SN under conditions of HFES. Moreover, we analyzed molecular mechanisms of the beneficial effect of losartan, an angiotensin II type I receptor (AT-1)blocker on HFES-induced nerve sprouting. Cell cultures of SN from the superior cervical ganglia (SCG) of neonatal rats were electrically stimulated for 48 h with a frequency of 5 or 50 Hz. HFES increased MMP-2 and MT1-MMP mRNA and protein expression, whereas TIMP-1 expression remained unchanged. Under conditions of HFES, we observed a shift from pro- to active-MMP-2 indicating an increase in MMP-2 enzyme activity. Specific pharmacological MMP-2 inhibition contributed to an increase in pro-NGF amount in the cell culture supernatant and significantly reduced HFES-induced neurite outgrowth. Losartan abolished HFES-induced nerve sprouting in a significant manner by preventing HFES-induced NGF, MMP-2, and MT1-MMP up-regulation. In summary, specific MMP-2 blockade prevents sympathetic nerve sprouting (SNS) by inhibition of pro-NGF conversion while losartan abolishes HFES-induced SNS by reducing total NGF, MMP-2 and MT1-MMP expression.

MeSH terms

  • Angiotensin Receptor Antagonists / pharmacology
  • Animals
  • Animals, Newborn
  • Cells, Cultured
  • Electric Stimulation / methods
  • Losartan / pharmacology
  • Matrix Metalloproteinase 14 / genetics
  • Matrix Metalloproteinase 14 / metabolism
  • Matrix Metalloproteinase 14 / physiology*
  • Matrix Metalloproteinase 2 / genetics
  • Matrix Metalloproteinase 2 / metabolism
  • Matrix Metalloproteinase 2 / physiology*
  • Nerve Growth Factors / metabolism*
  • Neurites / metabolism
  • Neurites / physiology*
  • Neurons / metabolism
  • Neurons / physiology
  • Protein Precursors / metabolism*
  • Protein Processing, Post-Translational / genetics*
  • Rats
  • Rats, Sprague-Dawley
  • Sympathetic Nervous System / metabolism*
  • Sympathetic Nervous System / physiology

Substances

  • Angiotensin Receptor Antagonists
  • Nerve Growth Factors
  • Protein Precursors
  • pro-nerve growth factor, rat
  • Matrix Metalloproteinase 2
  • Matrix Metalloproteinase 14
  • Losartan