HIV-1 upregulates VEGF in podocytes

J Am Soc Nephrol. 2008 May;19(5):877-83. doi: 10.1681/ASN.2007050629.

Abstract

HIV-associated nephropathy (HIVAN) is characterized by collapsing FSGS. Because transgenic mice with podocyte-specific overexpression of the vascular endothelial growth factor 164 (VEGF164) isoform also develop collapsing FSGS, we sought to determine whether VEGF plays a role in HIVAN. Compared with controls, immunohistochemistry revealed that kidneys from HIV-1-transgenic mice (Tg26) and from patients with HIVAN had greater expression of both VEGF and its transcriptional regulator, hypoxia-inducible factor 2alpha (HIF-2alpha). Similarly, mRNA and protein levels of VEGF and HIF-2alpha were increased in HIV-infected podocytes in vitro, and this transcriptional upregulation was found to be stimulated by the HIV viral protein Nef in a Src kinase-and Stat3-dependent manner. HIV-1 also upregulated VEGFR2 and its co-receptor neuropilin-1 and suppressed the expression of semaphorin 3a in the podocyte. Exogenous VEGF stimulated proliferation and de-differentiation of podocytes, which are features of collapsing FSGS, and VEGFR2 neutralizing antibodies reversed these features in podocytes infected with HIV-1 or isolated from Tg26 mice. In conclusion, HIV-1 induces VEGF and VEGFR2 expression in podocytes, and this may be a critical step in the pathogenesis of HIVAN.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • AIDS-Associated Nephropathy / metabolism*
  • AIDS-Associated Nephropathy / pathology
  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Basic Helix-Loop-Helix Transcription Factors / metabolism
  • Biopsy
  • Cell Line, Transformed
  • Gene Expression Regulation, Viral
  • HIV-1*
  • Humans
  • Mice
  • Mice, Transgenic
  • Podocytes / cytology
  • Podocytes / physiology*
  • Podocytes / virology*
  • RNA, Messenger / metabolism
  • Up-Regulation
  • Vascular Endothelial Growth Factor A / genetics*
  • Vascular Endothelial Growth Factor A / metabolism
  • Vascular Endothelial Growth Factor Receptor-2 / genetics
  • Vascular Endothelial Growth Factor Receptor-2 / metabolism

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • RNA, Messenger
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • vascular endothelial growth factor A, mouse
  • endothelial PAS domain-containing protein 1
  • Vascular Endothelial Growth Factor Receptor-2