TY - JOUR
T1 - Down-regulation of placental neuropilin-1 in fetal growth restriction
AU - Maulik, Dev
AU - De, Alok
AU - Ragolia, Louis
AU - Evans, Jodi
AU - Grigoryev, Dmitry
AU - Lankachandra, Kamani
AU - Mundy, David
AU - Muscat, Jolene
AU - Gerkovich, Mary M.
AU - Ye, Shui Qing
N1 - Funding Information:
Supported by University of Missouri–Kansas City School of Medicine intramural funding.
Publisher Copyright:
© 2016 The Authors.
PY - 2016/2/1
Y1 - 2016/2/1
N2 - Background Fetal growth restriction (FGR) is associated with adverse outcomes extending from fetal to adult life, and thus, constitutes a major health care challenge. Fetuses with progressive growth restriction show increasing impedance in the umbilical artery flow, which may become absent during end-diastole. Absent end-diastolic flow (AEDF) is associated with adverse perinatal outcomes including stillbirths and perinatal asphyxia. Placentas from such pregnancies demonstrate deficient fetoplacental vascular branching. Current evidence, moreover, indicates an antiangiogenic state in maternal circulation in several pregnancy complications including preeclampsia, small-for-gestational-age births, fetal death, and preterm labor. The angiogenic mediators in maternal circulation are predominantly of placental origin. Information, however, on the role of specific proangiogenic and antiangiogenic mechanisms operating at the placental level remains limited. Elucidation of these placenta-specific angiogenic mechanisms will not only extend our understanding of the causal pathway for restricted fetal growth but may also lead to the development of biomarkers that may allow early recognition of FGR. Objective We sought to test the hypothesis that fetoplacental angiogenic gene expression is altered in pregnancies complicated with FGR and umbilical artery Doppler AEDF. Study Design Placental samples were collected from FGR pregnancies complicated with umbilical artery Doppler AEDF (study group, n = 7), and from uncomplicated pregnancies (control group, n = 7), all delivered by cesarean during the last trimester of pregnancy. Angiogenic oligonucleotide microarray analysis was performed and was corroborated by quantitative real-time polymerase chain reaction, Western blot analysis, and immunohistochemistry. The Student t test with Bonferroni correction was used with P <.05 considered statistically significant. Independent groups t test was used to analyze the immunostain intensity scores with a P <.05 considered statistically significant. Results Our microarray results showed that among several differentially expressed angiogenic genes in the growth-restricted group, only the down-regulation of neuropilin (NRP)-1 was most significant (P <.0007). Quantitative real-time polymerase chain reaction confirmed a significantly lower NRP-1 gene expression in the FGR group than in the control group (mean ± SD cycle threshold: 0.624 ± 0.55 and 1.325 ± 0.84, respectively, P =.04). Western blot validated significantly lower NRP-1 protein expression in the FGR group than in the control group (mean ± SD NRP-1/β-actin ratio: 0.13 ± 0.04 and 0.34 ± 0.05, respectively, P <.001). Finally, immunohistochemistry of placental villi further corroborated a significantly decreased expression of NRP-1 in the FGR group (P =.006). Conclusion The study demonstrated significant down-regulation of placental NRP-1 expression in FGR pregnancies complicated with AEDF in umbilical artery. As NRP-1 is known to promote sprouting angiogenesis, its down-regulation may be involved in the deficient vascular branching observed in FGR placentas suggesting the presence of an antiangiogenic state. Further studies may elucidate such a causal role and may lead to the development of novel diagnostic and therapeutic tools.
AB - Background Fetal growth restriction (FGR) is associated with adverse outcomes extending from fetal to adult life, and thus, constitutes a major health care challenge. Fetuses with progressive growth restriction show increasing impedance in the umbilical artery flow, which may become absent during end-diastole. Absent end-diastolic flow (AEDF) is associated with adverse perinatal outcomes including stillbirths and perinatal asphyxia. Placentas from such pregnancies demonstrate deficient fetoplacental vascular branching. Current evidence, moreover, indicates an antiangiogenic state in maternal circulation in several pregnancy complications including preeclampsia, small-for-gestational-age births, fetal death, and preterm labor. The angiogenic mediators in maternal circulation are predominantly of placental origin. Information, however, on the role of specific proangiogenic and antiangiogenic mechanisms operating at the placental level remains limited. Elucidation of these placenta-specific angiogenic mechanisms will not only extend our understanding of the causal pathway for restricted fetal growth but may also lead to the development of biomarkers that may allow early recognition of FGR. Objective We sought to test the hypothesis that fetoplacental angiogenic gene expression is altered in pregnancies complicated with FGR and umbilical artery Doppler AEDF. Study Design Placental samples were collected from FGR pregnancies complicated with umbilical artery Doppler AEDF (study group, n = 7), and from uncomplicated pregnancies (control group, n = 7), all delivered by cesarean during the last trimester of pregnancy. Angiogenic oligonucleotide microarray analysis was performed and was corroborated by quantitative real-time polymerase chain reaction, Western blot analysis, and immunohistochemistry. The Student t test with Bonferroni correction was used with P <.05 considered statistically significant. Independent groups t test was used to analyze the immunostain intensity scores with a P <.05 considered statistically significant. Results Our microarray results showed that among several differentially expressed angiogenic genes in the growth-restricted group, only the down-regulation of neuropilin (NRP)-1 was most significant (P <.0007). Quantitative real-time polymerase chain reaction confirmed a significantly lower NRP-1 gene expression in the FGR group than in the control group (mean ± SD cycle threshold: 0.624 ± 0.55 and 1.325 ± 0.84, respectively, P =.04). Western blot validated significantly lower NRP-1 protein expression in the FGR group than in the control group (mean ± SD NRP-1/β-actin ratio: 0.13 ± 0.04 and 0.34 ± 0.05, respectively, P <.001). Finally, immunohistochemistry of placental villi further corroborated a significantly decreased expression of NRP-1 in the FGR group (P =.006). Conclusion The study demonstrated significant down-regulation of placental NRP-1 expression in FGR pregnancies complicated with AEDF in umbilical artery. As NRP-1 is known to promote sprouting angiogenesis, its down-regulation may be involved in the deficient vascular branching observed in FGR placentas suggesting the presence of an antiangiogenic state. Further studies may elucidate such a causal role and may lead to the development of novel diagnostic and therapeutic tools.
KW - antiangiogenic state
KW - fetal growth restriction
KW - immunohistochemistry
KW - microarrays
KW - neuropilin-1
KW - placental branching angiogenesis
KW - real-time polymerase chain reaction
KW - small for gestational age
KW - umbilical artery absent end-diastolic flow
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U2 - 10.1016/j.ajog.2015.09.068
DO - 10.1016/j.ajog.2015.09.068
M3 - Article
C2 - 26409917
AN - SCOPUS:84989773533
VL - 214
SP - 279.e1-279.e9
JO - American Journal of Obstetrics and Gynecology
JF - American Journal of Obstetrics and Gynecology
SN - 0002-9378
IS - 2
ER -