Expression and functional role of bone morphogenetic proteins (BMPs) in placenta during different stages of pregnancy in water buffalo (Bubalus bubalis).

The objective of this study was to document the expression and functional role of BMPs in the placental (caruncle; CAR, cotyledon; COT) during different stages of pregnancy in water buffalo. Samples collected from Early pregnancy 1 (EP1); Early pregnancy 2 (EP2), Mid pregnancy (MP), Late pregnancy (LP) while the third stage of oestrus cycle (NP) was taken as control. Also, the synergistic role of BMP4/BMP7 or combination on mRNA expression of vWF, PCNA, StAR, CYP11A1, 3βHSD, and BAX were studied in trophoblast cells cultured (TCC) during an early stage. The qPCR and immunoblotting studies revealed that BMP2, BMPR1A, BMPR1B, and BMPR2 mRNA level was significantly (p < 0.05) upregulated during early pregnancy in COTs while in CARs it was significantly upregulated (p < 0.05) during all the stages of pregnancy.BMP4 mRNA level was significantly upregulated (p < 0.05) during early pregnancy in COTs as well as in CARs. BMP6 expression was significantly upregulated (p < 0.05) during early and late stages of pregnancy. BMP7 mRNA level was upregulated (p < 0.05) during the late stage of pregnancy in COTs. At 100 ng/ml, the BMP4 maximally stimulated the transcripts of StAR, CYP11A1, and 3βHSD while BMP7 maximally stimulated the transcripts of 3βHSD that paralleled with P4 accretion in the media (P < 0.05). BMP4 as well as BMP7 upregulated the transcripts of PCNA, vWF, and downregulated BAX in the TCC (P < 0.05). In conclusion, BMPs are expressed in a regulated manner with stage-specific differences in the placenta and promotes the angiogenesis, proliferation, cell survivability, and steroidogenesis thereby regulating placental function in an autocrine/paracrine manner in water buffalo.