INVOLVEMENT OF WNT SIGNALING PATHWAY IN IMPARTING DEVELOPMENTAL COMPETENCE TO BUFFALO OOCYTES
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Date
2020
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Publisher
ICAR-NDRI, KARNAL
Abstract
Development ability of oocytes ultimately determines its ability to participate in
the process of fertilisation and its subsequentfate to grow as an embryo. It still
remains poorly understood on what makes only a few oocytes, out of many, to
become eligible for making a normal embryo. Wnt pathway has been reported
as one of the most salient pathway which affects the competence of the
oocytes by regulating the events in TGF Beta cascade. The next generation
sequencing data from our lab showed Wnt as significantly differentially
affected signaling pathways in the BCB- buffalo oocytes and its overactivity
can be attributed to lower embryo production in BCB- oocytes. In the present
study efforts were made to improve the overall in vitro oocyte maturation and
embryo development in buffalo oocytes by modulating the Wnt signaling
pathway in BCB- oocytes during IVM. Expression analysis of key molecules of
Wnt revealed a significantover activity of the pathway in BCB- oocytesat
mRNA and protein during initial 8 hours of the IVM. The overactive Wnt
pathway could be successfully inhibited by 100ng/ml of DKK1 while JW74
was found to be ineffective. There was no effect on percentage cleavage, 8-
16 cell but a significant improvement was seen in morula and blastocyst
percentage compared to BCB- control. The group of oocytes supplemented
with 100ng/ml of DKK1 showed a significant increase in the expression of
GVBD and MET genes compared to BCB- control signifying occurrence of this
event at correct time and in correct frequency in Wnt suppressed cases. Also
the genes GDF9, HAS2 and PTGS2and nuclear maturation rate showed
significant increase in BCB- oocytes with 100ng/ml DKK1 compared to BCBcontrol.
Our work concludes that inhibition of Wnt pathway under optimum
dose and duration can prove useful for embryonic development in buffaloes.