Methylation Dynamics of the PPAR Gamma (PPARγ) Gene during Adipogenic Differentiation of Human Bone Marrow Mesenchymal Stem Cells

 Epigenetics is crucial in differentiating mesenchymal stem cells (MSCs) into adipocytes. Specifically, DNA methylation, an epigenetic modification, regulates the expression of genes involved in this process. The peroxisome proliferator-activated receptor gamma (PPARγ) gene is a critical player in adipocyte differentiation, with epigenetic changes affecting its expression.

We isolated mesenchymal stem cells (MSCs) from the human bone marrow. The isolated MSCs were expanded and cultured in a differentiation medium for two weeks. DNA extraction was performed on undifferentiated and differentiated adipocytes after the culturing process. The methylation status of the promoter region of the PPARγ gene was assessed using methylation-specific primers (M for methylated and U for unmethylated) in a methylation-specific PCR (MSP) assay. This analysis involved the treatment of DNA samples with sodium bisulfite to convert unmethylated cytosine to uracil, thereby enabling the differentiation between methylated and unmethylated regions of the gene.

 The successful differentiation of MSCs into adipocytes was confirmed by the accumulation of lipid droplets within the differentiated cells, as visualized by the oil Red O dye staining. This observation provides strong evidence of the commitment of MSCs towards the adipogenic lineage and their ability to undergo adipocyte differentiation. Surprisingly, the MSP analysis revealed no significant changes in the methylation pattern of this gene following differentiation. The PPARγ gene promoter region exhibited an unmethylated status in both undifferentiated and differentiated states.

Our study revealed that additional genetic or epigenetic mechanisms control the expression of PPARγ during the adipogenic differentiation of mesenchymal stem cells. These findings highlight the regulatory role of PPARγ in the differentiation pathway from mesenchymal stem cells to adipocytes.