Semi-quantitative measurement of specific proteins in human cumulus cells using reverse phase protein array

Area of Science:

• Reproductive biology and assisted reproductive technology (ART).
• Biomarker discovery and validation.
• Proteomics and molecular diagnostics.

Background:

• Current oocyte competence assessment in ART relies on morphology, which has limited predictive value.
• Identifying reliable biomarkers for oocyte competence is crucial for improving ART success rates.
• Proteomic analysis of cumulus cells (CCs) offers a promising avenue for biomarker discovery.

Purpose of the Study:

• To investigate the potential of Reverse Phase Protein Array (RPPA) for identifying novel protein biomarkers of oocyte competence in human CCs.
• To evaluate the feasibility of using RPPA for detecting specific proteins in individual CCs.

Main Methods:

• Validated antibodies for RPPA by assessing siRNA-mediated knockdown efficiency via Western blotting (WB) and RPPA.
• Measured protein expression of VCL, SRC, and ERK2 in individual human CCs from four patients undergoing intracytoplasmic sperm injection.
• Utilized RPPA for quantitative protein detection in single CC samples.

Main Results:

• Antibodies for VCL and SRC proteins were successfully validated for RPPA.
• RPPA detected VCL, SRC, and ERK2 proteins in individual human CCs.
• While ERK2 expression was consistent, SRC protein levels varied significantly between patients and within individuals, indicating potential as a biomarker.

Conclusions:

• RPPA is a highly sensitive and quantitative technique capable of detecting specific proteins in minute biological samples like individual CCs.
• RPPA holds significant promise for clinical diagnostics in ART, enabling prediction of oocyte competence through robust protein biomarkers.
• Further validation of identified protein biomarkers like SRC could enhance embryo selection and improve ART success rates.