Maternal plasma proteomics in a rat model of pregnancy complications reveals immune and pro‐coagulant gene pathway activation

Abstract

Problem:The Brown Norway (BN) rat is a model of T-helper 2 immune diseases, and also a model of pregnancy disorders that include placental insufficiency, fetal loss, and pre-eclampsia-like symptoms. The aim of this study was to investigate the plasma proteomic/cytokine profile of pregnant BN rats in comparison to that of the Lewis (LEW) rat strain.Method of study: Plasma proteomics differences were studied at day 13 of pregnancy in pooled plasma samples by differential in-gel electrophoresis, and protein identification was performed by mass spectrometry. Key protein findings and predicted cytokine differences were validated by ELISA using plasma from rats at various pregnancy stages. Proteomics data were used for ingenuity pathway analysis (IPA). Results:In-gel analysis revealed 74 proteins with differential expression between BN and LEW pregnant dams. ELISA studies confirmed increased maternal plasma levels of complement 4, prothrombin, and C-reactive protein in BN compared to LEW pregnancies. LEW pregnancies showed higher maternal plasma levels of transthyretin and haptoglobin than BN pregnancies. Ingenuity pathway analysis revealed that BN pregnancies are characterized by activation of pro-coagulant, reactive oxygen species, and immune-mediated chronic inflammation pathways, and suggested increased interleukin 6 and decreased transforming growth factor-β1 as potential upstream events. Plasma cytokine analysis revealed that pregnant BN dams have a switch from anti-to pro-inflammatory cytokines with the opposite switch observed in pregnant LEW dams.Conclusion: Brown Norway rats show a maternal pro-inflammatory response to pregnancy that likely contributes to the reproductive outcomes observed in this rat strain. K E Y W O R D Simmune cytokines, maternal plasma, pregnancy, proteomics, strain differences

Renal functional, transcriptome, and methylome adaptations in pregnant Sprague Dawley and Brown Norway rats

“…Therefore, increased renal PDGF-BB is likely to contribute to the transcriptional and functional changes induced by pregnancy in the BN rat. In addition, the activation of renal RELA in BN pregnancies is in accordance with our previous study showing increased maternal plasma levels of interleukin 6, interferon gamma, and immunoglobulin G in pregnancy compared to non-pregnancy [ 26 ], and confirms the canonical pathway activation of ‘acute phase reaction’ in BN rat pregnancies. Of interest, although maternal plasma levels of pro-inflammatory mediators (such as interleukins and TNFs) are elevated in multiple pregnancy disorders [ 47 ], very little is known on the maternal organ-specific response to these circulatory factors.…”

“…Of interest, although maternal plasma levels of pro-inflammatory mediators (such as interleukins and TNFs) are elevated in multiple pregnancy disorders [ 47 ], very little is known on the maternal organ-specific response to these circulatory factors. This study in conjunction with our previous study on plasma proteomic changes in BN rat pregnancies [ 26 ] suggests that the maternal kidney responds to plasma pro-inflammatory cytokines with increases in both NF-kB and AP-1 pro-inflammatory transcription factor activation with subsequent changes in renal transcriptome.…”

“…We analyzed the annotated gene datasets obtained with stringer cutoffs of FC>1.5 and FDR <0.05 using the Ingenuity Pathway Analysis Program (Ingenuity Systems, Redwood City, CA), as previously described [ 26 ]. The pathways identified were ranked based on the ratio of the number of molecules in a given pathway that are altered in the present dataset vs. the total known molecules that constitute the pathways.…”

Iron nitrosyl complexes are formed from nitrite in the human placenta

“…In the present work, we confirm the existence of FeNOs in sheep placental tissue, as well as in the placenta of Sprague Dawley, Lewis, and Brown Norway rat strains. We also note that placentas from the Brown Norway rats, which serve as a model of preeclampsia and placental insufficiency (27,28), have higher total NOx and FeNO than placentas from either the Sprague Dawley or the Lewis rats. Together, these results point toward a physiological function of FeNOs in the placenta.…”

Human cord plasma proteomic analysis reveals sexually dimorphic proteins associated with intrauterine growth restriction

“…Several proteomic studies, related to IUGR, have focused on maternal and placental factors with very few studies on umbilical cord blood. Molecular profiling of maternal plasma have revealed alterations in lipid metabolism, activation of pro-coagulant, reactive oxygen species, nutrient transport, energy metabolism, and immune-mediated chronic inflammation pathways [7][8][9][10][11]. In the IUGR placental proteome, most detected proteins are related to oxidative stress, cellular oxidation and detoxication, apoptosis, angiogenesis, energy transduction, cell proliferation, differentiation, and intracellular signaling [12][13][14][15].…”