RNA-Seq Analysis of Blastocoel Fluid-Conditioned Media From Euploid Embryos Reveals Higher Expression of Specific Mitochondrial Genes in Media From Embryos Associated With Positive Implantation Outcomes [ID 2683525

Abstract

INTRODUCTION: This retrospective study measured gene expression using RNA-seq of blastocoel fluid-conditioned media from euploid embryos with known implantation status to identify genes associated with implantation outcomes. METHODS: Blastocoel fluid-conditioned media was obtained after biopsy (ploidy status via NextGen sequencing) of intracytoplasmic sperm injection-generated day 5 blastocysts. Media used for RNA-seq were from 10 euploid blastocysts with known implantation outcomes. RNA was extracted, libraries were prepared, NextSeq500 sequencing was performed, and then sequences were aligned to the human genome. After quality control, the total gene count was 15,284. DESeq2 was used to test for differential gene expression. Raw read counts were normalized and variance stabilizing transformations were applied across samples. Log fold change shrinkage methods were used for gene visualization and rankings. Wald test statistic was used to compare implantation outcomes. Adjusted false-discovery rate P value of <.05 was considered statistically significant for differential expressed genes. RESULTS: Several genes were identified in this analysis revealing differential expression when comparing implantation outcomes. Of interest were two mitochondrial genes (DNAJC19 and MT-TK) and the NOA1 (required for mitochondrial function) with higher expression in media from embryos resulting in successful implantation. CONCLUSION: This study implicates mitochondrial function as a key player during preimplantation development that may affect implantation outcomes. DNAJC19 acts to bring proteins into the mitochondrial matrix, MT-TK encodes a mitochondrial tRNA, and NOA1 is a GTP binding protein residing in the mitochondria. The media samples in this study were collected from euploid blastocysts; therefore, gene expression differences detected represent potential molecular markers for predicting implantation success.