Differential expression of VEGF isoforms and receptors in knee joint menisci under systemic hypoxia.
Vascular endothelial growth factor (VEGF) gene gives rise to several distinct isoforms of VEGF, which differ in their expression patterns as well as their biochemical and biological properties. We examined the expression levels of VEGF isoforms and their receptors in the medial and lateral meniscus of rabbits under normal physiologic conditions as well their expression levels after 8 and 24 h of systemic normobaric hypoxia (13%). VEGF121 is the most abundant VEGF isoform in the medial and lateral meniscus, followed by VEGF165, VEGF189, and VEGF183. While the soluble VEGF121 and VEGF165 are only upregulated at 8 h of hypoxia, the membrane-bound VEGF183 and VEGF189 are further increased at 24 h. VEGFR-2 is expressed at a much higher level than VEGFR-1 under normal conditions, and both receptors are upregulated under hypoxia. Differential expression levels under normoxia as well as a differential response to hypoxia may indicate different functions of VEGF isoforms in the meniscus.
Laboratory for Skeletal Disorders and Rehabilitation, Department of Orthopaedic Surgery, Children's Hospital, Harvard Medical School, 300 Longwood Ave., Boston, MA 02115, USA. Jochen.Hofstaetter@childrens.harvard.edu
Jochen G
JG
Hofstaetter
Fawzy A
FA
Saad
Raymond E
RE
Samuel
Livius
L
Wunderlich
Yeong-Hoon
YH
Choi
Melvin J
MJ
Glimcher
D000818:Animals; D002356:Cartilage / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D000860:Hypoxia; D007719:Knee Joint / Q000378:metabolism*; D020033:Protein Isoforms / Q000737:chemistry*; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis* / Q000737:chemistry; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000096:biosynthesis* / Q000737:chemistry; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000096:biosynthesis* / Q000737:chemistry
D017931:DNA Primers; D020033:Protein Isoforms; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D012313:RNA; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2; D012194:RNA-Directed DNA Polymerase