Human placental hypoxia-inducible factor-1alpha expression correlates with clinical outcomes in chronic hypoxia in vivo.
Placental hypoxia is causally implicated in fetal growth restriction and preeclampsia, with both occurring more frequently at high altitude (>2700 m; HA). The nuclear transcription factor hypoxia-inducible factor (HIF) may facilitate placental oxygen transport at HA by increasing erythropoiesis and placental angiogenesis. We therefore investigated HIF expression and its regulatory mechanisms in placentas from normal pregnancies at high (3100 m), moderate (1600 m), and sea level (75 m) altitudes. Moderate-altitude and sea level placentas did not differ, but HIF-1alpha and the von Hippel-Lindau tumor suppressor protein were overexpressed in HA placentas. The ability of von Hippel-Lindau tumor suppressor protein to form the E3 ubiquitin protein ligase complex, required for HIF-1alpha degradation, was unaltered in HA placentas. mRNA for factor-inhibiting HIF, a negative modulator of HIF-1alpha transactivation, was increased, but protein levels were diminished. Elevated HIF-1alpha likely contributed to the significant increase we report in HIF-1alpha downstream target proteins, transforming growth factor beta3 in the placenta, and vascular endothelial growth factor and erythropoietin in the maternal circulation. These circulating markers and lowered birth to placental weight ratios correlated with increased HIF-1alpha, thereby linking molecular and systemic physiological data. The HA response to chronic hypoxia resembles preeclampsia in several aspects, illustrating the utility of the HA model in understanding placental pathologies.
Zamudio
Stacy
S
Department of Obstetrics, Gynecology and Women's Health, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA. stacy.zamudio@umdnj.edu
Wu
Yuanhong
Y
Ietta
Francesca
F
Rolfo
Alessandro
A
Cross
Ashley
A
Wheeler
Timothy
T
Post
Martin
M
Illsley
Nicholas P
NP
Caniggia
Isabella
I
D000328:Adult; D000531:Altitude; D000818:Animals; D001724:Birth Weight; D044842:Cullin Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D005865:Gestational Age; D006801:Humans; D000860:Hypoxia; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D006899:Mixed Function Oxygenases; D009929:Organ Size; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000235:genetics / Q000378:metabolism
C105153:CUL2 protein, human; D044842:Cullin Proteins; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012097:Repressor Proteins; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D006899:Mixed Function Oxygenases; C439790:HIF1AN protein, human; D051794:Von Hippel-Lindau Tumor Suppressor Protein; C497446:VHL protein, human