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ANGPT2

Wednesday 21 March 2007

Angiopoietin-2 (Ang-2 or ANGPT2) modulates Tie-2 receptor activation. In mouse kidney maturation, Ang-2 is expressed in arteries, with lower levels in tubules, whereas Tie-2 is expressed by endothelia.

Animal models

- Ang-2 null mice mutants

  • In Ang-2 null mice mutants, alpha SMA, desmin, and PDGFR beta prominently immunolocalized in cortical peritubular locations. Some alpha SMA-positive cells were closely associated with CD31- and Tie-2-positive peritubular capillary endothelia, and some of the alpha SMA-positive cells expressed PDGFR beta, desmin, and neural/glial cell 2 (NG2), consistent with a pericyte-like identity.
  • Immunoblotting suggested an increase of total and tyrosine-phosphorylated Tie-2 proteins in null mutant versus wild-type kidneys, and electron microscopy confirmed disorganized capillaries and adjacent cells in cortical peritubular spaces in mutant neonate kidneys.
  • Ang-2 deficiency causes dysmorphogenesis of cortical peritubular capillaries, with adjacent cells expressing pericyte-like markers; we speculate the latter effect is caused by disturbed paracrine signaling between endothelial and surrounding mesenchymal precursor cells.

References

- Pitera JE, Woolf AS, Gale NW, Yancopoulos GD, Yuan HT. Dysmorphogenesis of kidney cortical peritubular capillaries in angiopoietin-2-deficient mice. Am J Pathol. 2004 Dec;165(6):1895-906. PMID: 15579434